diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index ab3f5994..b491c600 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -15,11 +15,8 @@ env:
 
 jobs:
   main:
-    runs-on: [self-hosted,FlipperZero]
+    runs-on: [self-hosted,FlipperZeroShell]
     steps:
-      - name: 'Cleanup workspace'
-        uses: AutoModality/action-clean@v1
-
       - name: 'Decontaminate previous build leftovers'
         run: |
           if [ -d .git ]
@@ -32,12 +29,8 @@ jobs:
         uses: actions/checkout@v2
         with:
           fetch-depth: 0
-          submodules: true
           ref: ${{ github.event.pull_request.head.sha }}
 
-      - name: 'Build docker image'
-        uses: ./.github/actions/docker
-
       - name: 'Make artifacts directory'
         run: |
           test -d artifacts && rm -rf artifacts || true
@@ -71,40 +64,34 @@ jobs:
         run: |
           tar czpf artifacts/flipper-z-any-scripts-${{steps.names.outputs.suffix}}.tgz scripts
 
-      - name: 'Build the firmware in docker'
-        uses: ./.github/actions/docker
-        with:
-          run: |
-            set -e
-            for TARGET in ${TARGETS}
-            do
-              ./fbt TARGET_HW=`echo ${TARGET} | sed 's/f//'` updater_package ${{ startsWith(github.ref, 'refs/tags') && 'DEBUG=0 COMPACT=1' || '' }}
-            done
+      - name: 'Build the firmware'
+        run: |
+          set -e
+          for TARGET in ${TARGETS}
+          do
+            FBT_TOOLCHAIN_PATH=/opt ./fbt TARGET_HW=`echo ${TARGET} | sed 's/f//'` updater_package ${{ startsWith(github.ref, 'refs/tags') && 'DEBUG=0 COMPACT=1' || '' }}
+          done
 
       - name: 'Move upload files'
         if: ${{ !github.event.pull_request.head.repo.fork }}
-        uses: ./.github/actions/docker
-        with:
-          run: |
-            set -e
-            for TARGET in ${TARGETS}
-            do
-              mv dist/${TARGET}-*/* artifacts/
-            done
+        run: |
+          set -e
+          for TARGET in ${TARGETS}
+          do
+            mv dist/${TARGET}-*/* artifacts/
+          done
 
       - name: 'Bundle self-update package'
         if: ${{ !github.event.pull_request.head.repo.fork }}
-        uses: ./.github/actions/docker
-        with:
-          run: |
-            set -e
-            for UPDATEBUNDLE in artifacts/*/
-            do
-              BUNDLE_NAME=`echo $UPDATEBUNDLE | cut -d'/' -f2`
-              echo Packaging ${BUNDLE_NAME}
-              tar czpf artifacts/flipper-z-${BUNDLE_NAME}.tgz -C artifacts ${BUNDLE_NAME}
-              rm -rf artifacts/${BUNDLE_NAME}
-            done
+        run: |
+          set -e
+          for UPDATEBUNDLE in artifacts/*/
+          do
+            BUNDLE_NAME=`echo $UPDATEBUNDLE | cut -d'/' -f2`
+            echo Packaging ${BUNDLE_NAME}
+            tar czpf artifacts/flipper-z-${BUNDLE_NAME}.tgz -C artifacts ${BUNDLE_NAME}
+            rm -rf artifacts/${BUNDLE_NAME}
+          done
 
       - name: "Check for uncommited changes"
         run: |
@@ -117,29 +104,23 @@ jobs:
 
       - name: 'Bundle core2 firmware'
         if: ${{ !github.event.pull_request.head.repo.fork }}
-        uses: ./.github/actions/docker
-        with:
-          run: |
-            ./fbt copro_dist
-            tar czpf artifacts/flipper-z-any-core2_firmware-${{steps.names.outputs.suffix}}.tgz -C assets core2_firmware
+        run: |
+          FBT_TOOLCHAIN_PATH=/opt ./fbt copro_dist
+          tar czpf artifacts/flipper-z-any-core2_firmware-${{steps.names.outputs.suffix}}.tgz -C assets core2_firmware
 
       - name: 'Upload artifacts to update server'
         if: ${{ !github.event.pull_request.head.repo.fork }}
-        uses: burnett01/rsync-deployments@5.1
-        with:
-          switches: -avzP --delete --mkpath
-          path: artifacts/
-          remote_path: "${{ secrets.RSYNC_DEPLOY_BASE_PATH }}${{steps.names.outputs.artifacts-path}}/"
-          remote_host: ${{ secrets.RSYNC_DEPLOY_HOST }}
-          remote_port: ${{ secrets.RSYNC_DEPLOY_PORT }}
-          remote_user: ${{ secrets.RSYNC_DEPLOY_USER }}
-          remote_key: ${{ secrets.RSYNC_DEPLOY_KEY }}
+        run: |
+          echo "${{ secrets.RSYNC_DEPLOY_KEY }}" > deploy_key;
+          chmod 600 ./deploy_key;
+          rsync -avzP --mkpath \
+              -e 'ssh -p ${{ secrets.RSYNC_DEPLOY_PORT }} -i ./deploy_key' \
+              artifacts/ ${{ secrets.RSYNC_DEPLOY_USER }}@${{ secrets.RSYNC_DEPLOY_HOST }}:"${{ secrets.RSYNC_DEPLOY_BASE_PATH }}${{steps.names.outputs.artifacts-path}}/";
+          rm ./deploy_key;
 
       - name: 'Trigger update server reindex'
         if: ${{ !github.event.pull_request.head.repo.fork }}
-        uses: wei/curl@master
-        with:
-          args: -X POST -F 'key=${{ secrets.REINDEX_KEY }}' ${{ secrets.REINDEX_URL }}
+        run: curl -X POST -F 'key=${{ secrets.REINDEX_KEY }}' ${{ secrets.REINDEX_URL }}
 
       - name: 'Find Previous Comment'
         if: ${{ !github.event.pull_request.head.repo.fork && github.event.pull_request }}
@@ -165,11 +146,8 @@ jobs:
 
   compact:
     if: ${{ !startsWith(github.ref, 'refs/tags') }}
-    runs-on: [self-hosted,FlipperZero]
+    runs-on: [self-hosted,FlipperZeroShell]
     steps:
-      - name: 'Cleanup workspace'
-        uses: AutoModality/action-clean@v1
-
       - name: 'Decontaminate previous build leftovers'
         run: |
           if [ -d .git ]
@@ -185,9 +163,6 @@ jobs:
           submodules: true
           ref: ${{ github.event.pull_request.head.sha }}
 
-      - name: 'Build docker image'
-        uses: ./.github/actions/docker
-
       - name: 'Generate suffix and folder name'
         id: names
         run: |
@@ -207,12 +182,10 @@ jobs:
           echo "WORKFLOW_BRANCH_OR_TAG=${BRANCH_OR_TAG}" >> $GITHUB_ENV
           echo "DIST_SUFFIX=${SUFFIX}" >> $GITHUB_ENV
 
-      - name: 'Build the firmware in docker'
-        uses: ./.github/actions/docker
-        with:
-          run: |
-            set -e
-            for TARGET in ${TARGETS}
-            do
-              ./fbt TARGET_HW=`echo ${TARGET} | sed 's/f//'` updater_package DEBUG=0 COMPACT=1
-            done
+      - name: 'Build the firmware'
+        run: |
+          set -e
+          for TARGET in ${TARGETS}
+          do
+            FBT_TOOLCHAIN_PATH=/opt ./fbt TARGET_HW=`echo ${TARGET} | sed 's/f//'` updater_package DEBUG=0 COMPACT=1
+          done
diff --git a/.github/workflows/build_toolchain.yml b/.github/workflows/build_toolchain.yml
deleted file mode 100644
index 452dfbee..00000000
--- a/.github/workflows/build_toolchain.yml
+++ /dev/null
@@ -1,46 +0,0 @@
-name: 'Build toolchain Docker image'
-
-on:
-  push:
-    branches:
-      - dev
-    tags:
-      - '*'
-
-jobs:
-  build:
-    runs-on: ubuntu-latest
-    steps:
-      - name: Checkout code
-        uses: actions/checkout@v2
-        with:
-          fetch-depth: 0
-      - name: Docker meta
-        id: meta
-        uses: docker/metadata-action@v3
-        with:
-          images: flipperdevices/flipperzero-toolchain
-          flavor: latest=${{ startsWith(github.ref, 'refs/tags/') && !endsWith(github.ref, 'rc')}}
-          tags: |
-            type=ref,event=branch
-            type=ref,event=tag
-      - name: Set up QEMU
-        uses: docker/setup-qemu-action@v1
-      - name: Set up Docker Buildx
-        uses: docker/setup-buildx-action@v1
-      - name: Login to DockerHub
-        uses: docker/login-action@v1
-        with:
-          username: ${{ secrets.DOCKERHUB_USERNAME }}
-          password: ${{ secrets.DOCKERHUB_TOKEN }}
-      - name: Build and push
-        id: docker_build
-        uses: docker/build-push-action@v2
-        with:
-          context: docker/
-          push: true
-          tags: ${{ steps.meta.outputs.tags }}
-          labels: ${{ steps.meta.outputs.labels }}
-          platforms: linux/amd64,linux/arm64
-          cache-from: type=registry,ref=flipperdevices/flipperzero-toolchain:buildcache
-          cache-to: type=registry,ref=flipperdevices/flipperzero-toolchain:buildcache,mode=max
diff --git a/.github/workflows/check_submodules.yml b/.github/workflows/check_submodules.yml
index b02f9a8d..f9699be8 100644
--- a/.github/workflows/check_submodules.yml
+++ b/.github/workflows/check_submodules.yml
@@ -1,17 +1,47 @@
-name: 'Check submodules'
+name: 'Check submodules branch'
 
 on:
+  push:
+    branches:
+      - dev
+      - "release*"
+    tags:
+      - '*'
   pull_request:
 
 jobs:
-  protobuf:
-    runs-on: ubuntu-latest
+  check_protobuf:
+    runs-on: [self-hosted, FlipperZeroShell]
     steps:
-    - name: 'Checkout code'
-      uses: actions/checkout@v2
-    - name: 'Check submodule commit branch'
-      uses: jtmullen/submodule-branch-check-action@v1
-      with:
-        path: assets/protobuf
-        branch: dev
-        fetch_depth: 50
+      - name: 'Decontaminate previous build leftovers'
+        run: |
+          if [ -d .git ]
+          then
+            git submodule status \
+              || git checkout `git rev-list --max-parents=0 HEAD | tail -n 1`
+          fi
+
+      - name: 'Checkout code'
+        uses: actions/checkout@v2
+        with:
+          fetch-depth: 0
+
+      - name: 'Check protobuf branch'
+        run: |
+          SUB_PATH="assets/protobuf";
+          SUB_BRANCH="dev";
+          SUB_COMMITS_MIN=40;
+          cd "$SUB_PATH";
+          SUBMODULE_HASH="$(git rev-parse HEAD)";
+          BRANCHES=$(git branch -r --contains "$SUBMODULE_HASH");
+          COMMITS_IN_BRANCH="$(git rev-list --count dev)";
+          if [ $COMMITS_IN_BRANCH -lt $SUB_COMMITS_MIN ]; then
+            echo "::set-output name=fails::error";
+            echo "::error::Error: Too low commits in $SUB_BRANCH of submodule $SUB_PATH: $COMMITS_IN_BRANCH(expected $SUB_COMMITS_MIN+)";
+            exit 1;
+          fi
+          if ! grep -q "/$SUB_BRANCH" <<< "$BRANCHES"; then
+            echo "::set-output name=fails::error";
+            echo "::error::Error: Submodule $SUB_PATH is not on branch $SUB_BRANCH";
+            exit 1;
+          fi
diff --git a/.github/workflows/lint_c.yml b/.github/workflows/lint_c.yml
index f834586d..aaff396e 100644
--- a/.github/workflows/lint_c.yml
+++ b/.github/workflows/lint_c.yml
@@ -1,6 +1,6 @@
 name: 'Lint C/C++ with clang-format'
 
-on: 
+on:
   push:
     branches:
       - dev
@@ -14,11 +14,8 @@ env:
 
 jobs:
   lint_c_cpp:
-    runs-on: [self-hosted,FlipperZero]
+    runs-on: [self-hosted,FlipperZeroShell]
     steps:
-      - name: 'Cleanup workspace'
-        uses: AutoModality/action-clean@v1
-
       - name: 'Decontaminate previous build leftovers'
         run: |
           if [ -d .git ]
@@ -31,23 +28,10 @@ jobs:
         uses: actions/checkout@v2
         with:
           fetch-depth: 0
-          submodules: true
-
-      - name: 'Docker cache'
-        uses: satackey/action-docker-layer-caching@v0.0.11
-        continue-on-error: true
-        with:
-          key: docker-cache-${{ hashFiles('docker/**') }}-{hash}
-          restore-keys: docker-cache-${{ hashFiles('docker/**') }}-
-
-      - name: 'Build docker image'
-        uses: ./.github/actions/docker
 
       - name: 'Check code formatting'
         id: syntax_check
-        uses: ./.github/actions/docker
-        with:
-          run: SET_GH_OUTPUT=1 ./fbt lint
+        run: SET_GH_OUTPUT=1 FBT_TOOLCHAIN_PATH=/opt ./fbt lint
 
       - name: Report code formatting errors
         if: failure() && steps.syntax_check.outputs.errors && github.event.pull_request
@@ -59,4 +43,4 @@ jobs:
             ```
             ${{ steps.syntax_check.outputs.errors }}
             ```
-            You might want to run `docker compose exec dev make format` for an auto-fix.
+            You might want to run `./fbt format` for an auto-fix.
diff --git a/.github/workflows/lint_python.yml b/.github/workflows/lint_python.yml
index e665378b..c059f434 100644
--- a/.github/workflows/lint_python.yml
+++ b/.github/workflows/lint_python.yml
@@ -1,6 +1,6 @@
 name: 'Python Lint'
 
-on: 
+on:
   push:
     branches:
       - dev
@@ -11,11 +11,8 @@ on:
 
 jobs:
   lint_python:
-    runs-on: ubuntu-latest
+    runs-on: [self-hosted,FlipperZeroShell]
     steps:
-      - name: 'Cleanup workspace'
-        uses: AutoModality/action-clean@v1
-
       - name: 'Decontaminate previous build leftovers'
         run: |
           if [ -d .git ]
@@ -29,8 +26,5 @@ jobs:
         with:
           fetch-depth: 0
 
-      - name: 'Setup python'
-        uses: actions/setup-python@v2
-
-      - name: 'Check python code with black'
-        uses: psf/black@20.8b1
+      - name: 'Check code formatting'
+        run: SET_GH_OUTPUT=1 FBT_TOOLCHAIN_PATH=/opt ./fbt lint_py
diff --git a/.github/workflows/reindex.yml b/.github/workflows/reindex.yml
index 78f9cbea..ea850e70 100644
--- a/.github/workflows/reindex.yml
+++ b/.github/workflows/reindex.yml
@@ -7,9 +7,8 @@ on:
 jobs:
   reindex:
     name: 'Reindex updates'
-    runs-on: [self-hosted,FlipperZero]
+    runs-on: [self-hosted,FlipperZeroShell]
     steps:
       - name: Trigger reindex
-        uses: wei/curl@master
-        with:
-          args: -X POST -F 'key=${{ secrets.REINDEX_KEY }}' ${{ secrets.REINDEX_URL }}
+        run: |
+          curl -X POST -F 'key=${{ secrets.REINDEX_KEY }}' ${{ secrets.REINDEX_URL }}
diff --git a/SConstruct b/SConstruct
index 178ae192..fe731e35 100644
--- a/SConstruct
+++ b/SConstruct
@@ -7,6 +7,7 @@
 # construction of certain targets behind command-line options.
 
 import os
+import subprocess
 
 EnsurePythonVersion(3, 8)
 
@@ -231,6 +232,46 @@ distenv.PhonyTarget(
     LINT_SOURCES=firmware_env["LINT_SOURCES"],
 )
 
+# PY_LINT_SOURCES contains recursively-built modules' SConscript files + application manifests
+# Here we add additional Python files residing in repo root
+firmware_env.Append(
+    PY_LINT_SOURCES=[
+        # Py code folders
+        "site_scons",
+        "scripts",
+        # Extra files
+        "applications/extapps.scons",
+        "SConstruct",
+        "firmware.scons",
+        "fbt_options.py",
+    ]
+)
+
+
+black_commandline = "@${PYTHON3} -m black ${PY_BLACK_ARGS} ${PY_LINT_SOURCES}"
+black_base_args = ["--include", '"\\.scons|\\.py|SConscript|SConstruct"']
+
+distenv.PhonyTarget(
+    "lint_py",
+    black_commandline,
+    PY_BLACK_ARGS=[
+        "--check",
+        "--diff",
+        *black_base_args,
+    ],
+    PY_LINT_SOURCES=firmware_env["PY_LINT_SOURCES"],
+)
+
+distenv.PhonyTarget(
+    "format_py",
+    black_commandline,
+    PY_BLACK_ARGS=black_base_args,
+    PY_LINT_SOURCES=firmware_env["PY_LINT_SOURCES"],
+)
+
+# Start Flipper CLI via PySerial's miniterm
+distenv.PhonyTarget("cli", "${PYTHON3} scripts/serial_cli.py")
+
 
 # Find blackmagic probe
 
diff --git a/documentation/fbt.md b/documentation/fbt.md
index 7e56672e..c658ce20 100644
--- a/documentation/fbt.md
+++ b/documentation/fbt.md
@@ -41,6 +41,8 @@ FBT keeps track of internal dependencies, so you only need to build the highest-
 - `blackmagic` - debug firmware with Blackmagic probe (WiFi dev board)
 - `openocd` - just start OpenOCD
 - `get_blackmagic` - output blackmagic address in gdb remote format. Useful for IDE integration
+- `lint`, `format` - run clang-tidy on C source code to check and reformat it according to `.clang-format` specs
+- `lint_py`, `format_py` - run [black](https://black.readthedocs.io/en/stable/index.html) on Python source code, build system files & application manifests 
 
 ### Firmware targets
 
diff --git a/fbt b/fbt
index 0ea572b1..981489dd 100755
--- a/fbt
+++ b/fbt
@@ -4,14 +4,20 @@
 # unofficial strict mode
 set -eu;
 
-SCONS_DEFAULT_FLAGS="-Q --warn=target-not-built";
+# private variables
 SCRIPT_PATH="$(cd "$(dirname "$0")" && pwd -P)";
+SCONS_DEFAULT_FLAGS="-Q --warn=target-not-built";
 
-if [ -z "${FBT_NOENV:-}" ]; then
+# public variables
+FBT_NOENV="${FBT_NOENV:-""}";
+FBT_NO_SYNC="${FBT_NO_SYNC:-""}";
+FBT_TOOLCHAIN_PATH="${FBT_TOOLCHAIN_PATH:-$SCRIPT_PATH}";
+
+if [ -z "$FBT_NOENV" ]; then
     . "$SCRIPT_PATH/scripts/toolchain/fbtenv.sh";
 fi
 
-if [ -z "${FBT_NO_SYNC:-}" ]; then
+if [ -z "$FBT_NO_SYNC" ]; then
     if [ ! -d "$SCRIPT_PATH/.git" ]; then
         echo "\".git\" directory not found, please clone repo via \"git clone --recursive\"";
         exit 1;
@@ -19,4 +25,4 @@ if [ -z "${FBT_NO_SYNC:-}" ]; then
     git submodule update --init;
 fi
 
-python3 "$SCRIPT_PATH/lib/scons/scripts/scons.py" $SCONS_DEFAULT_FLAGS "$@"
\ No newline at end of file
+python3 "$SCRIPT_PATH/lib/scons/scripts/scons.py" $SCONS_DEFAULT_FLAGS "$@"
diff --git a/lib/loclass.scons b/lib/loclass.scons
index ba43dd6e..a657f042 100644
--- a/lib/loclass.scons
+++ b/lib/loclass.scons
@@ -4,8 +4,6 @@ env.Append(
     CPPPATH=[
         "#/lib/loclass",
     ],
-    CPPDEFINES=[
-    ],
 )
 
 
diff --git a/lib/mbedtls.scons b/lib/mbedtls.scons
index 35de7e6f..1b0bec87 100644
--- a/lib/mbedtls.scons
+++ b/lib/mbedtls.scons
@@ -5,8 +5,6 @@ env.Append(
         "#/lib/mbedtls",
         "#/lib/mbedtls/include",
     ],
-    CPPDEFINES=[
-    ],
 )
 
 
diff --git a/scripts/serial_cli.py b/scripts/serial_cli.py
new file mode 100644
index 00000000..e07e6bfb
--- /dev/null
+++ b/scripts/serial_cli.py
@@ -0,0 +1,14 @@
+import logging
+import subprocess
+from flipper.utils.cdc import resolve_port
+
+
+def main():
+    logger = logging.getLogger()
+    if not (port := resolve_port(logger, "auto")):
+        return 1
+    subprocess.call(["python3", "-m", "serial.tools.miniterm", "--raw", port, "230400"])
+
+
+if __name__ == "__main__":
+    main()
diff --git a/scripts/toolchain/fbtenv.cmd b/scripts/toolchain/fbtenv.cmd
index 1a9af5a4..471ce835 100644
--- a/scripts/toolchain/fbtenv.cmd
+++ b/scripts/toolchain/fbtenv.cmd
@@ -13,7 +13,7 @@ if not [%FBT_NOENV%] == [] (
     exit /b 0
 )
 
-set "FLIPPER_TOOLCHAIN_VERSION=3"
+set "FLIPPER_TOOLCHAIN_VERSION=8"
 set "FBT_TOOLCHAIN_ROOT=%FBT_ROOT%\toolchain\i686-windows"
 
 
diff --git a/scripts/toolchain/fbtenv.sh b/scripts/toolchain/fbtenv.sh
index 55bc89b0..654b1fe0 100755
--- a/scripts/toolchain/fbtenv.sh
+++ b/scripts/toolchain/fbtenv.sh
@@ -1,54 +1,211 @@
 #!/bin/sh
 
-# unofficial strict mode
-set -eu;
+# shellcheck disable=SC2034,SC2016,SC2086
 
-FLIPPER_TOOLCHAIN_VERSION="3";
+# public variables
+DEFAULT_SCRIPT_PATH="$(pwd -P)";
+SCRIPT_PATH="${SCRIPT_PATH:-$DEFAULT_SCRIPT_PATH}";
+FBT_TOOLCHAIN_VERSION="${FBT_TOOLCHAIN_VERSION:-"8"}";
+FBT_TOOLCHAIN_PATH="${FBT_TOOLCHAIN_PATH:-$SCRIPT_PATH}";
 
-get_kernel_type()
+fbtenv_check_sourced()
 {
-    SYS_TYPE="$(uname -s)"
+    case "${ZSH_EVAL_CONTEXT:-""}" in *:file:*)
+        return 0;;
+    esac
+    case ${0##*/} in dash|-dash|bash|-bash|ksh|-ksh|sh|-sh)
+        return 0;;
+    esac
+    if [ "$(basename $0)" = "fbt" ]; then
+        return 0;
+    fi
+    echo "Running this script manually is wrong, please source it";
+    echo "Example:";
+    printf "\tsource scripts/toolchain/fbtenv.sh\n";
+    return 1;
+}
+
+fbtenv_check_script_path()
+{
+    if [ ! -x "$SCRIPT_PATH/fbt" ]; then
+        echo "Please source this script being into flipperzero-firmware root directory, or specify 'SCRIPT_PATH' manually";
+        echo "Example:";
+        printf "\tSCRIPT_PATH=lang/c/flipperzero-firmware source lang/c/flipperzero-firmware/scripts/fbtenv.sh\n";
+        echo "If current directory is right, type 'unset SCRIPT_PATH' and try again"
+        return 1;
+    fi
+    return 0;
+}
+
+fbtenv_get_kernel_type()
+{
+    SYS_TYPE="$(uname -s)";
+    ARCH_TYPE="$(uname -m)";
+    if [ "$ARCH_TYPE" != "x86_64" ] && [ "$SYS_TYPE" != "Darwin" ]; then
+        echo "Now we provide toolchain only for x86_64 arhitecture, sorry..";
+        return 1;
+    fi
     if [ "$SYS_TYPE" = "Darwin" ]; then
-        TOOLCHAIN_PATH="toolchain/x86_64-darwin";
+        fbtenv_check_rosetta || return 1;
+        TOOLCHAIN_ARCH_DIR="$FBT_TOOLCHAIN_PATH/toolchain/x86_64-darwin";
+        TOOLCHAIN_URL="https://update.flipperzero.one/builds/toolchain/gcc-arm-none-eabi-10.3-x86_64-darwin-flipper-$FBT_TOOLCHAIN_VERSION.tar.gz";
     elif [ "$SYS_TYPE" = "Linux" ]; then
-        TOOLCHAIN_PATH="toolchain/x86_64-linux";
+        TOOLCHAIN_ARCH_DIR="$FBT_TOOLCHAIN_PATH/toolchain/x86_64-linux";
+        TOOLCHAIN_URL="https://update.flipperzero.one/builds/toolchain/gcc-arm-none-eabi-10.3-x86_64-linux-flipper-$FBT_TOOLCHAIN_VERSION.tar.gz";
     elif echo "$SYS_TYPE" | grep -q "MINGW"; then
         echo "In MinGW shell use \"fbt.cmd\" instead of \"fbt\"";
-        exit 1;
+        return 1;
     else
-        echo "Sorry, your system is not supported. Please report your configuration to us.";
-        exit 1;
+        echo "Your system is not recognized. Sorry.. Please report us your configuration.";
+        return 1;
     fi
+    return 0;
 }
 
-check_download_toolchain()
+fbtenv_check_rosetta()
 {
-    if [ ! -d "$SCRIPT_PATH/$TOOLCHAIN_PATH" ]; then
-        download_toolchain;
-    elif [ ! -f "$SCRIPT_PATH/$TOOLCHAIN_PATH/VERSION" ]; then
-        download_toolchain;
-    elif [ "$(cat "$SCRIPT_PATH/$TOOLCHAIN_PATH/VERSION")" -ne "$FLIPPER_TOOLCHAIN_VERSION" ]; then
-        download_toolchain;
+    if [ "$ARCH_TYPE" = "arm64" ]; then
+        if ! /usr/bin/pgrep -q oahd; then
+            echo "Flipper Zero Toolchain needs Rosetta2 to run under Apple Silicon";
+            echo "Please instal it by typing 'softwareupdate --install-rosetta --agree-to-license'";
+            return 1;
+        fi
     fi
+    return 0;
 }
 
-download_toolchain()
+fbtenv_check_tar()
 {
-    chmod 755 "$SCRIPT_PATH/scripts/toolchain/unix-toolchain-download.sh";
-    "$SCRIPT_PATH/scripts/toolchain/unix-toolchain-download.sh" "$FLIPPER_TOOLCHAIN_VERSION" || exit 1;
+    printf "Checking tar..";
+    if ! tar --version > /dev/null 2>&1; then
+        echo "no";
+        return 1;
+    fi
+    echo "yes";
+    return 0;
 }
 
-main()
+fbtenv_check_downloaded_toolchain()
 {
-    if [ -z "${SCRIPT_PATH:-}" ]; then
-        echo "Manual running of this script is not allowed.";
-        exit 1;
+    printf "Checking downloaded toolchain tgz..";
+    if [ ! -f "$FBT_TOOLCHAIN_PATH/toolchain/$TOOLCHAIN_TAR" ]; then
+        echo "no";
+        return 1;
     fi
-    get_kernel_type;  # sets TOOLCHAIN_PATH
-    check_download_toolchain;
-    PATH="$SCRIPT_PATH/$TOOLCHAIN_PATH/python/bin:$PATH";
-    PATH="$SCRIPT_PATH/$TOOLCHAIN_PATH/bin:$PATH";
-    PATH="$SCRIPT_PATH/$TOOLCHAIN_PATH/protobuf/bin:$PATH";
-    PATH="$SCRIPT_PATH/$TOOLCHAIN_PATH/openocd/bin:$PATH";
+    echo "yes";
+    return 0;
 }
-main;
+
+fbtenv_download_toolchain_tar()
+{
+    echo "Downloading toolchain:";
+    mkdir -p "$FBT_TOOLCHAIN_PATH/toolchain" || return 1;
+    "$DOWNLOADER" $DOWNLOADER_ARGS "$FBT_TOOLCHAIN_PATH/toolchain/$TOOLCHAIN_TAR" "$TOOLCHAIN_URL" || return 1;
+    echo "done";
+    return 0;
+}
+
+fbtenv_remove_old_tooclhain()
+{
+    printf "Removing old toolchain (if exist)..";
+    rm -rf "${TOOLCHAIN_ARCH_DIR}";
+    echo "done";
+}
+
+fbtenv_show_unpack_percentage()
+{
+    LINE=0;
+    while read -r line; do
+        LINE=$(( LINE + 1 ));
+        if [ $(( LINE % 300 )) -eq 0 ]; then
+            printf "#";
+        fi
+    done
+    echo " 100.0%";
+}
+
+fbtenv_unpack_toolchain()
+{
+    echo "Unpacking toolchain:";
+    tar -xvf "$FBT_TOOLCHAIN_PATH/toolchain/$TOOLCHAIN_TAR" -C "$FBT_TOOLCHAIN_PATH/toolchain" 2>&1 | fbtenv_show_unpack_percentage;
+    mkdir -p "$FBT_TOOLCHAIN_PATH/toolchain" || return 1;
+    mv "$FBT_TOOLCHAIN_PATH/toolchain/$TOOLCHAIN_DIR" "$TOOLCHAIN_ARCH_DIR" || return 1;
+    echo "done";
+    return 0;
+}
+
+fbtenv_clearing()
+{
+    printf "Clearing..";
+    rm -rf "${FBT_TOOLCHAIN_PATH:?}/toolchain/$TOOLCHAIN_TAR";
+    echo "done";
+    return 0;
+}
+
+fbtenv_curl_wget_check()
+{
+    printf "Checking curl..";
+    if ! curl --version > /dev/null 2>&1; then
+        echo "no";
+        printf "Checking wget..";
+        if ! wget --version > /dev/null 2>&1; then
+            echo "no";
+            echo "No curl or wget found in your PATH";
+            echo "Please provide it or download this file:";
+            echo;
+            echo "$TOOLCHAIN_URL";
+            echo;
+            echo "And place in $FBT_TOOLCHAIN_PATH/toolchain/ dir mannualy";
+            return 1;
+        fi
+        echo "yes"
+        DOWNLOADER="wget";
+        DOWNLOADER_ARGS="--show-progress --progress=bar:force -qO";
+        return 0;
+    fi
+    echo "yes"
+    DOWNLOADER="curl";
+    DOWNLOADER_ARGS="--progress-bar -SLo";
+    return 0;
+}
+
+fbtenv_check_download_toolchain()
+{
+    if [ ! -d "$TOOLCHAIN_ARCH_DIR" ]; then
+        fbtenv_download_toolchain || return 1;
+    elif [ ! -f "$TOOLCHAIN_ARCH_DIR/VERSION" ]; then
+        fbtenv_download_toolchain || return 1;
+    elif [ "$(cat "$TOOLCHAIN_ARCH_DIR/VERSION")" -ne "$FBT_TOOLCHAIN_VERSION" ]; then
+        fbtenv_download_toolchain || return 1;
+    fi
+    return 0;
+}
+
+fbtenv_download_toolchain()
+{
+    fbtenv_check_tar || return 1;
+    TOOLCHAIN_TAR="$(basename "$TOOLCHAIN_URL")";
+    TOOLCHAIN_DIR="$(echo "$TOOLCHAIN_TAR" | sed "s/-$FBT_TOOLCHAIN_VERSION.tar.gz//g")";
+    if ! fbtenv_check_downloaded_toolchain; then
+        fbtenv_curl_wget_check || return 1;
+        fbtenv_download_toolchain_tar;
+    fi
+    fbtenv_remove_old_tooclhain;
+    fbtenv_unpack_toolchain || { fbtenv_clearing && return 1; };
+    fbtenv_clearing;
+    return 0;
+}
+
+fbtenv_main()
+{
+    fbtenv_check_sourced || return 1;
+    fbtenv_check_script_path || return 1;
+    fbtenv_get_kernel_type || return 1;
+    fbtenv_check_download_toolchain || return 1;
+    PATH="$TOOLCHAIN_ARCH_DIR/python/bin:$PATH";
+    PATH="$TOOLCHAIN_ARCH_DIR/bin:$PATH";
+    PATH="$TOOLCHAIN_ARCH_DIR/protobuf/bin:$PATH";
+    PATH="$TOOLCHAIN_ARCH_DIR/openocd/bin:$PATH";
+}
+
+fbtenv_main;
diff --git a/scripts/toolchain/unix-toolchain-download.sh b/scripts/toolchain/unix-toolchain-download.sh
deleted file mode 100755
index 386be2a3..00000000
--- a/scripts/toolchain/unix-toolchain-download.sh
+++ /dev/null
@@ -1,135 +0,0 @@
-#!/bin/sh
-# shellcheck disable=SC2086,SC2034
-
-# unofficial strict mode
-set -eu;
-
-check_system()
-{
-    VER="$1";  # toolchain version
-    printf "Checking kernel type..";
-    SYS_TYPE="$(uname -s)"
-    if [ "$SYS_TYPE" = "Darwin" ]; then
-        echo "darwin";
-        TOOLCHAIN_URL="https://update.flipperzero.one/builds/toolchain/gcc-arm-none-eabi-10.3-x86_64-darwin-flipper-$VER.tar.gz";
-        TOOLCHAIN_PATH="toolchain/x86_64-darwin";
-    elif [ "$SYS_TYPE" = "Linux" ]; then
-        echo "linux";
-        TOOLCHAIN_URL="https://update.flipperzero.one/builds/toolchain/gcc-arm-none-eabi-10.3-x86_64-linux-flipper-$VER.tar.gz";
-        TOOLCHAIN_PATH="toolchain/x86_64-linux";
-    else
-        echo "unsupported.";
-        echo "Your system is unsupported.. sorry..";
-        exit 1;
-    fi
-}
-
-check_tar()
-{
-    printf "Checking tar..";
-    if ! tar --version > /dev/null 2>&1; then
-        echo "no";
-        exit 1;
-    fi
-    echo "yes";
-}
-
-
-curl_wget_check()
-{
-    printf "Checking curl..";
-    if ! curl --version > /dev/null 2>&1; then
-        echo "no";
-        printf "Checking wget..";
-        if ! wget --version > /dev/null 2>&1; then
-            echo "no";
-            echo "No curl or wget found in your PATH.";
-            echo "Please provide it or download this file:";
-            echo;
-            echo "$TOOLCHAIN_URL";
-            echo;
-            echo "And place in repo root dir mannualy.";
-            exit 1;
-        fi
-        echo "yes"
-        DOWNLOADER="wget";
-        DOWNLOADER_ARGS="--show-progress --progress=bar:force -qO";
-        return;
-    fi
-    echo "yes"
-    DOWNLOADER="curl";
-    DOWNLOADER_ARGS="--progress-bar -SLo";
-}
-
-check_downloaded_toolchain()
-{
-    printf "Checking downloaded toolchain tgz..";
-    if [ -f "$REPO_ROOT/$TOOLCHAIN_TAR" ]; then
-        echo "yes";
-        return 0;
-    fi
-    echo "no";
-    return 1;
-}
-
-download_toolchain()
-{
-    echo "Downloading toolchain:";
-    "$DOWNLOADER" $DOWNLOADER_ARGS "$REPO_ROOT/$TOOLCHAIN_TAR" "$TOOLCHAIN_URL";
-    echo "done";
-}
-
-remove_old_tooclhain()
-{
-    printf "Removing old toolchain (if exist)..";
-    rm -rf "${REPO_ROOT:?}/$TOOLCHAIN_PATH";
-    echo "done";
-}
-
-show_unpack_percentage()
-{
-    LINE=0;
-    while read -r line; do
-        LINE=$(( LINE + 1 ));
-        if [ $(( LINE % 300 )) -eq 0 ]; then
-            printf "#";
-        fi
-    done
-    echo " 100.0%";
-}
-
-unpack_toolchain()
-{
-    echo "Unpacking toolchain:";
-    tar -xvf "$REPO_ROOT/$TOOLCHAIN_TAR" -C "$REPO_ROOT/" 2>&1 | show_unpack_percentage;
-    mkdir -p "$REPO_ROOT/toolchain";
-    mv "$REPO_ROOT/$TOOLCHAIN_DIR" "$REPO_ROOT/$TOOLCHAIN_PATH/";
-    echo "done";
-}
-
-clearing()
-{
-    printf "Clearing..";
-    rm -rf "${REPO_ROOT:?}/$TOOLCHAIN_TAR";
-    echo "done";
-}
-
-main()
-{
-    SCRIPT_PATH="$(cd "$(dirname "$0")" && pwd -P)"
-    REPO_ROOT="$(cd "$SCRIPT_PATH/../../" && pwd)";
-    check_system "$1";  # recives TOOLCHAIN_VERSION, defines TOOLCHAIN_URL and TOOLCHAIN_PATH
-    check_tar;
-    TOOLCHAIN_TAR="$(basename "$TOOLCHAIN_URL")";
-    TOOLCHAIN_DIR="$(echo "$TOOLCHAIN_TAR" | sed "s/-$VER.tar.gz//g")";
-    if ! check_downloaded_toolchain; then
-        curl_wget_check;
-        download_toolchain;
-    fi
-    remove_old_tooclhain;
-    unpack_toolchain;
-}
-
-trap clearing EXIT;
-trap clearing 2;  # SIGINT not coverable by EXIT
-main "$1";  # toochain version
diff --git a/site_scons/site_tools/fbt_apps.py b/site_scons/site_tools/fbt_apps.py
index aaf08bfa..2cd63b70 100644
--- a/site_scons/site_tools/fbt_apps.py
+++ b/site_scons/site_tools/fbt_apps.py
@@ -21,9 +21,9 @@ def LoadApplicationManifests(env):
     for entry in env.Glob("#/applications/*", ondisk=True, source=True):
         if isinstance(entry, SCons.Node.FS.Dir) and not str(entry).startswith("."):
             try:
-                appmgr.load_manifest(
-                    os.path.join(entry.abspath, "application.fam"), entry.name
-                )
+                app_manifest_file_path = os.path.join(entry.abspath, "application.fam")
+                appmgr.load_manifest(app_manifest_file_path, entry.name)
+                env.Append(PY_LINT_SOURCES=[app_manifest_file_path])
             except FlipperManifestException as e:
                 warn(WarningOnByDefault, str(e))
 
@@ -67,6 +67,7 @@ def generate(env):
                     build_apps_c,
                     "${APPSCOMSTR}",
                 ),
+                suffix=".c",
             ),
         }
     )
diff --git a/site_scons/site_tools/sconsmodular.py b/site_scons/site_tools/sconsmodular.py
index db0cb8f3..778c664e 100644
--- a/site_scons/site_tools/sconsmodular.py
+++ b/site_scons/site_tools/sconsmodular.py
@@ -1,5 +1,6 @@
 import posixpath
 import os
+from SCons.Errors import UserError
 
 
 def BuildModule(env, module):
@@ -8,9 +9,9 @@ def BuildModule(env, module):
     if not os.path.exists(module_sconscript):
         module_sconscript = posixpath.join(src_dir, f"{module}.scons")
         if not os.path.exists(module_sconscript):
-            print(f"Cannot build module {module}: scons file not found")
-            Exit(2)
+            raise UserError(f"Cannot build module {module}: scons file not found")
 
+    env.Append(PY_LINT_SOURCES=[module_sconscript])
     return env.SConscript(
         module_sconscript,
         variant_dir=posixpath.join(env.subst("$BUILD_DIR"), module),