diff --git a/.github/workflows/cross-bootstrap-tools.yml b/.github/workflows/cross-bootstrap-tools.yml
index ddb543dc3b068..3e2ebc50bcb2c 100644
--- a/.github/workflows/cross-bootstrap-tools.yml
+++ b/.github/workflows/cross-bootstrap-tools.yml
@@ -6,64 +6,141 @@ on:
     branches: [ main, 'stable/14', 'stable/13' ]
     paths:
       - 'sys/**'
-      - 'stand/**'
 
-      - 'bin/**'
-      - 'sbin/**'
-      - 'usr.bin/**'
-      - 'usr.sbin/**'
-
-      # XXX What to build here?
       - 'Makefile'
       - 'Makefile.inc1'
 
       - '**/cross-bootstrap-tools.yml'
-
-      - '!**.[1-9]' # Ignore manpages
   pull_request:
     branches: [ main ]
     paths:
       - 'sys/**'
-      - 'stand/**'
-
-      - 'bin/**'
-      - 'sbin/**'
-      - 'usr.bin/**'
-      - 'usr.sbin/**'
 
-      # XXX What to build here?
       - 'Makefile'
       - 'Makefile.inc1'
 
       - '**/cross-bootstrap-tools.yml'
-
-      - '!**.[1-9]' # Ignore manpages
   workflow_dispatch:
 
 permissions:
   contents: read
 
 jobs:
-  modified_files:
-    name: get modified files
+  setup:
+    name: setup
     runs-on: ubuntu-latest
     outputs:
-      changes: ${{ steps.changes.outputs.files }}
+      archs: ${{ steps.match.outputs.archs }}
+      make_targets: ${{ steps.match.outputs.make_targets }}
     steps:
-      - uses: actions/checkout@v4
-      - name: get modified files
-        id: changes
+      - name: checkout
+        uses: actions/checkout@v4
+      - name: paths filter (kernel)
+        uses: dorny/paths-filter@v3
+        id: kern_filter
+        with:
+          base: ${{ github.ref_name }}
+          filters: |
+            amd64:
+              - 'sys/amd64/**'
+            i386:
+              - 'sys/i386/**'
+            aarch64:
+              - 'sys/arm64/**'
+            armv7:
+              - 'sys/arm/**'
+            powerpc: &ppc
+              - 'sys/powerpc/**'
+            powerpc64:
+              - *ppc
+            powerpc64le:
+              - *ppc
+            riscv64:
+              - 'sys/riscv/**'
+            all:
+              - '**/cross-bootstrap-tools.yml'
+      - name: paths filter (world)
+        uses: dorny/paths-filter@v3
+        id: world_filter
+        with:
+          base: ${{ github.ref_name }}
+          filters: |
+            amd64:
+              - 'sys/amd64/**.h'
+            i386:
+              - 'sys/i386/**.h'
+            aarch64:
+              - 'sys/arm64/**.h'
+            armv7:
+              - 'sys/arm/**.h'
+            powerpc: &ppc
+              - 'sys/powerpc/**.h'
+            powerpc64:
+              - *ppc
+            powerpc64le:
+              - *ppc
+            riscv64:
+              - 'sys/riscv/**.h'
+            all:
+              - '**/cross-bootstrap-tools.yml'
+      - name: match paths
+        shell: python
+        id: match
         run: |
-          echo "files=$(git diff --name-only --diff-filter=ACMRT ${{ github.event.push.before }} ${{ github.sha }} | xargs)"
-          echo "files=$(git diff --name-only --diff-filter=ACMRT ${{ github.event.push.before }} ${{ github.sha }} | xargs)" >> $GITHUB_OUTPUT
+          import os
+          import json
+
+          all = ["amd64", "armv7", "aarch64", "i386", "powerpc", "powerpc64", "powerpc64le", "riscv64"]
+          out = open(os.environ['GITHUB_OUTPUT'], "a")
+
+          if ${{ steps.kern_filter.outputs.changes }} != []:
+            make_targets = ["buildkernel"]
+
+            if ${{ steps.kern_filter.outputs.all }}:
+              kern_archs = all
+            else:
+              kern_archs = json.loads(${{ steps.kern_filter.outputs.changes }})
+            
+            kern_excl = list(set(all) ^ set(kern_archs))
+            exclude = '['
+            for a in kern_excl:
+              exclude += "{ make_target: buildkernel, target_arch: " + a + "},"
+            exclude = exclude[:-1] + ']'
+
+            out.write("kern_excl=" + exclude + '\n')
+
+          if ${{ steps.world_filter.outputs.changes }} != []:
+            make_targets += "buildworld"
+
+            if ${{ steps.world_filter.outputs.all }}:
+              world_archs = all             
+            else:
+              world_archs = json.loads(${{ steps.world_filter.outputs.changes }})
+
+            world_excl = list(set(all) ^ set(kern_archs))
+            exclude = '['
+            for a in world_excl:
+              exclude += "{ make_target: buildworld, target_arch: " + a + "},"
+            exclude = exclude[:-1] + ']'
+  
+            out.write("world_excl=" + exclude + '\n')
+
+          print("kern_archs: ", kern_archs)
+          print("world_archs: ", world_archs)
+
+          out.write("make_targets=" + json.dumps(make_targets) + '\n')
+          out.write("archs=" + json.dumps(list(set(world_archs + kern_archs))) + '\n')
+          out.close()
   build:
-    name: ${{ matrix.target_arch }} buildkernel on ${{ matrix.os }} (${{ matrix.compiler }})
+    name: ${{ matrix.target_arch }} ${{ matrix.make_target }} on ${{ matrix.os }} (${{ matrix.compiler }})
     runs-on: ${{ matrix.os }}
-    needs: modified_files
+    needs: setup
     strategy:
       fail-fast: false
       matrix:
-        target_arch: [ amd64, aarch64, powerpc ]
+        target_arch: ${{ fromJSON(needs.setup.outputs.archs) }}
+        make_target: ${{ fromJSON(needs.setup.outputs.make_targets) }}
+
         os: [ ubuntu-22.04, ubuntu-24.04, macos-latest ]
         include:
           # TODO: both Ubuntu and macOS have bmake packages, we should try them instead of bootstrapping our own copy.
@@ -79,17 +156,27 @@ jobs:
             compiler: clang-18
             cross-bindir: /opt/homebrew/opt/llvm@18/bin
             pkgs: bmake libarchive llvm@18
+
+          # Correspoding TARGET for TARGET_ARCH
           - target_arch: amd64
             target: amd64
+          - target_arch: armv7
+            target: arm
           - target_arch: aarch64
             target: arm64
+          - target_arch: i386
+            target: i386
           - target_arch: powerpc
             target: powerpc
+          - target_arch: powerpc64
+            target: powerpc
+          - target_arch: powerpc64le
+            target: powerpc
+          - target_arch: riscv64
+            target: riscv
+        exclude: ${{ needs.setup.outputs.exclude }}
     steps:
       - uses: actions/checkout@v4
-      - name: check modified files
-        run: |
-          echo ${{ needs.modified_files.outputs.changes }} && exit 1
       - name: install packages (Ubuntu)
         if: runner.os == 'Linux'
         run: |