diff --git a/.github/actions/checkout/action.yml b/.github/actions/checkout/action.yml
index f14f5d306d..85bedf2eae 100644
--- a/.github/actions/checkout/action.yml
+++ b/.github/actions/checkout/action.yml
@@ -28,7 +28,7 @@ runs:
     shell: bash
     run: |
       node src/electron/script/generate-deps-hash.js
-      DEPSHASH="v1-src-cache-$(cat src/electron/.depshash)"
+      DEPSHASH="v2-src-cache-$(cat src/electron/.depshash)"
       echo "DEPSHASH=$DEPSHASH" >> $GITHUB_ENV
       echo "CACHE_FILE=$DEPSHASH.tar" >> $GITHUB_ENV
       if [ "${{ inputs.target-platform }}" = "win" ]; then
@@ -109,7 +109,7 @@ runs:
         echo "target_os=['$TARGET_OS']" >> ./.gclient
       fi
 
-      ELECTRON_USE_THREE_WAY_MERGE_FOR_PATCHES=1 e d gclient sync --with_branch_heads --with_tags -vv
+      ELECTRON_DEPOT_TOOLS_WIN_TOOLCHAIN=0 DEPOT_TOOLS_WIN_TOOLCHAIN=0 ELECTRON_USE_THREE_WAY_MERGE_FOR_PATCHES=1 e d gclient sync --with_branch_heads --with_tags
       if [[ "${{ inputs.is-release }}" != "true" ]]; then
         # Re-export all the patches to check if there were changes.
         python3 src/electron/script/export_all_patches.py src/electron/patches/config.json
@@ -187,7 +187,9 @@ runs:
     shell: bash
     run: |
       echo "Uncompressed src size: $(du -sh src | cut -f1 -d' ')"
-      tar -cf $CACHE_FILE src
+      # Named .tar but zstd-compressed; the sas-sidecar's filename allowlist
+      # only permits .tar/.tgz so we keep the extension and decode on restore.
+      tar -cf - src | zstd -T0 --long=30 -f -o $CACHE_FILE
       echo "Compressed src to $(du -sh $CACHE_FILE | cut -f1 -d' ')"
       cp ./$CACHE_FILE $CACHE_DRIVE/
   - name: Persist Src Cache
diff --git a/.github/actions/restore-cache-aks/action.yml b/.github/actions/restore-cache-aks/action.yml
index b614b3a076..2522193274 100644
--- a/.github/actions/restore-cache-aks/action.yml
+++ b/.github/actions/restore-cache-aks/action.yml
@@ -31,7 +31,7 @@ runs:
       fi
 
       mkdir temp-cache
-      tar -xf $cache_path -C temp-cache
+      zstd -d --long=30 -c $cache_path | tar -xf - -C temp-cache
       echo "Unzipped cache is $(du -sh temp-cache/src | cut -f1)"
 
       if [ -d "temp-cache/src" ]; then
diff --git a/.github/actions/restore-cache-azcopy/action.yml b/.github/actions/restore-cache-azcopy/action.yml
index ee8fe62905..7099ea8fda 100644
--- a/.github/actions/restore-cache-azcopy/action.yml
+++ b/.github/actions/restore-cache-azcopy/action.yml
@@ -61,9 +61,9 @@ runs:
         echo "Cache is empty - exiting"
         exit 1
       fi
-      
+
       mkdir temp-cache
-      tar -xf $DEPSHASH.tar -C temp-cache
+      zstd -d --long=30 -c $DEPSHASH.tar | tar -xf - -C temp-cache
       echo "Unzipped cache is $(du -sh temp-cache/src | cut -f1)"
 
       if [ -d "temp-cache/src" ]; then
@@ -85,19 +85,17 @@ runs:
 
   - name: Unzip and Ensure Src Cache (Windows)
     if: ${{ inputs.target-platform == 'win' }}
-    shell: powershell
+    shell: bash
     run: |
-      $src_cache = "$env:DEPSHASH.tar"
-      $cache_size = $(Get-Item $src_cache).length
-      Write-Host "Downloaded cache is $cache_size"
-      if ($cache_size -eq 0) {
-        Write-Host "Cache is empty - exiting"
+      echo "Downloaded cache is $(du -sh $DEPSHASH.tar | cut -f1)"
+      if [ `du $DEPSHASH.tar | cut -f1` = "0" ]; then
+        echo "Cache is empty - exiting"
         exit 1
-      }
+      fi
 
-      $TEMP_DIR=New-Item -ItemType Directory -Path temp-cache
-      $TEMP_DIR_PATH = $TEMP_DIR.FullName
-      C:\ProgramData\Chocolatey\bin\7z.exe -y -snld20 x $src_cache -o"$TEMP_DIR_PATH"
+      mkdir temp-cache
+      zstd -d --long=30 -c $DEPSHASH.tar | tar -xf - -C temp-cache
+      rm -f $DEPSHASH.tar
 
   - name: Move Src Cache (Windows)
     if: ${{ inputs.target-platform == 'win' }}
@@ -112,9 +110,6 @@ runs:
           Write-Host "Relocating Cache"
           Remove-Item -Recurse -Force src
           Move-Item temp-cache\src src
-
-          Write-Host "Deleting zip file"
-          Remove-Item -Force $src_cache
         }
         if (-Not (Test-Path "src\third_party\blink")) {
           Write-Host "Cache was not correctly restored - exiting"
diff --git a/.github/workflows/pipeline-electron-docs-only.yml b/.github/workflows/pipeline-electron-docs-only.yml
index b3e22f3168..038822c57d 100644
--- a/.github/workflows/pipeline-electron-docs-only.yml
+++ b/.github/workflows/pipeline-electron-docs-only.yml
@@ -35,7 +35,7 @@ jobs:
     - name: Generate DEPS Hash
       run: |
         node src/electron/script/generate-deps-hash.js
-        DEPSHASH=v1-src-cache-$(cat src/electron/.depshash)
+        DEPSHASH=v2-src-cache-$(cat src/electron/.depshash)
         echo "DEPSHASH=$DEPSHASH" >> $GITHUB_ENV
         echo "CACHE_PATH=$DEPSHASH.tar" >> $GITHUB_ENV
     - name: Restore src cache via AKS
diff --git a/.github/workflows/pipeline-segment-electron-build.yml b/.github/workflows/pipeline-segment-electron-build.yml
index 1a67587ab5..ce507de736 100644
--- a/.github/workflows/pipeline-segment-electron-build.yml
+++ b/.github/workflows/pipeline-segment-electron-build.yml
@@ -156,7 +156,7 @@ jobs:
     - name: Generate DEPS Hash
       run: |
         node src/electron/script/generate-deps-hash.js
-        DEPSHASH=v1-src-cache-$(cat src/electron/.depshash)
+        DEPSHASH=v2-src-cache-$(cat src/electron/.depshash)
         echo "DEPSHASH=$DEPSHASH" >> $GITHUB_ENV
         echo "CACHE_PATH=$DEPSHASH.tar" >> $GITHUB_ENV
     - name: Restore src cache via AZCopy
diff --git a/.github/workflows/pipeline-segment-electron-clang-tidy.yml b/.github/workflows/pipeline-segment-electron-clang-tidy.yml
index c7ddb39403..8924322e40 100644
--- a/.github/workflows/pipeline-segment-electron-clang-tidy.yml
+++ b/.github/workflows/pipeline-segment-electron-clang-tidy.yml
@@ -80,7 +80,7 @@ jobs:
     - name: Generate DEPS Hash
       run: |
         node src/electron/script/generate-deps-hash.js
-        DEPSHASH=v1-src-cache-$(cat src/electron/.depshash)
+        DEPSHASH=v2-src-cache-$(cat src/electron/.depshash)
         echo "DEPSHASH=$DEPSHASH" >> $GITHUB_ENV
         echo "CACHE_PATH=$DEPSHASH.tar" >> $GITHUB_ENV
     - name: Restore src cache via AZCopy
diff --git a/.github/workflows/pipeline-segment-electron-gn-check.yml b/.github/workflows/pipeline-segment-electron-gn-check.yml
index 0c28e2c8c1..2e23a1466c 100644
--- a/.github/workflows/pipeline-segment-electron-gn-check.yml
+++ b/.github/workflows/pipeline-segment-electron-gn-check.yml
@@ -81,7 +81,7 @@ jobs:
     - name: Generate DEPS Hash
       run: |
         node src/electron/script/generate-deps-hash.js
-        DEPSHASH=v1-src-cache-$(cat src/electron/.depshash)
+        DEPSHASH=v2-src-cache-$(cat src/electron/.depshash)
         echo "DEPSHASH=$DEPSHASH" >> $GITHUB_ENV
         echo "CACHE_PATH=$DEPSHASH.tar" >> $GITHUB_ENV
     - name: Restore src cache via AZCopy
diff --git a/.github/workflows/pipeline-segment-electron-publish.yml b/.github/workflows/pipeline-segment-electron-publish.yml
index 5de845ba94..cddeb6028a 100644
--- a/.github/workflows/pipeline-segment-electron-publish.yml
+++ b/.github/workflows/pipeline-segment-electron-publish.yml
@@ -165,7 +165,7 @@ jobs:
       - name: Generate DEPS Hash
         run: |
           node src/electron/script/generate-deps-hash.js
-          DEPSHASH=v1-src-cache-$(cat src/electron/.depshash)
+          DEPSHASH=v2-src-cache-$(cat src/electron/.depshash)
           echo "DEPSHASH=$DEPSHASH" >> $GITHUB_ENV
           echo "CACHE_PATH=$DEPSHASH.tar" >> $GITHUB_ENV
       - name: Restore src cache via AZCopy