diff --git a/.github/workflows/test-build-aarch64.yml b/.github/workflows/test-build-aarch64.yml
index fa11a85d3e..f65c89ceec 100644
--- a/.github/workflows/test-build-aarch64.yml
+++ b/.github/workflows/test-build-aarch64.yml
@@ -26,10 +26,52 @@ jobs:
           submodules: true
 
       - name: Workaround for sources.list
-        run: sudo sed -i 's|http://azure.archive.ubuntu.com/ubuntu/|http://mirror.arizona.edu/ubuntu/|g' /etc/apt/sources.list
+        run: |
+            # Replace sources
+
+            set -euxo pipefail
+
+            # Peek (what repos are active now)
+            apt-cache policy
+            grep -RInE '^(deb|Types|URIs)' /etc/apt || true
+
+            # Enable nullglob so *.list/*.sources that don't exist don't break sed
+            shopt -s nullglob
+
+            echo "Replace sources.list (legacy)"
+            sudo sed -i \
+              -e "s|https\?://azure\.archive\.ubuntu\.com/ubuntu/?|http://mirror.arizona.edu/ubuntu/|g" \
+              /etc/apt/sources.list || true
+
+            echo "Replace sources.list.d/*.list (legacy)"
+            for f in /etc/apt/sources.list.d/*.list; do
+              sudo sed -i \
+                -e "s|https\?://azure\.archive\.ubuntu\.com/ubuntu/?|http://mirror.arizona.edu/ubuntu/|g" \
+                "$f"
+            done
+
+            echo "Replace sources.list.d/*.sources (deb822)"
+            for f in /etc/apt/sources.list.d/*.sources; do
+              sudo sed -i \
+                -e "s|https\?://azure\.archive\.ubuntu\.com/ubuntu/?|http://mirror.arizona.edu/ubuntu/|g" \
+                -e "s|https\?://azure\.archive\.ubuntu\.com|http://mirror.arizona.edu|g" \
+                "$f"
+            done
+
+            echo "Fix /etc/apt/apt-mirrors.txt (used by URIs: mirror+file:...)"
+            if grep -qE '^[[:space:]]*https?://azure\.archive\.ubuntu\.com/ubuntu/?' /etc/apt/apt-mirrors.txt; then
+              # Replace azure with our mirror (idempotent)
+              sudo sed -i 's|https\?://azure\.archive\.ubuntu\.com/ubuntu/|http://mirror.arizona.edu/ubuntu/|g' /etc/apt/apt-mirrors.txt
+            fi
+
+            # Peek (verify changes)
+            grep -RIn "azure.archive.ubuntu.com" /etc/apt || true
+            grep -RInE '^(deb|Types|URIs)' /etc/apt || true
+            echo "--- apt-mirrors.txt ---"
+            cat /etc/apt/apt-mirrors.txt || true
 
       - name: Update repository
-        run: sudo apt-get update
+        run: sudo apt-get update -o Acquire::Retries=3
 
       - name: Install dependencies
         run: |
diff --git a/.github/workflows/test-build-lms.yml b/.github/workflows/test-build-lms.yml
index 16519d934a..2181ea28d1 100644
--- a/.github/workflows/test-build-lms.yml
+++ b/.github/workflows/test-build-lms.yml
@@ -26,7 +26,11 @@ jobs:
           submodules: true
 
       - name: Workaround for sources.list
-        run: sudo sed -i 's|http://azure.archive.ubuntu.com/ubuntu/|http://mirror.arizona.edu/ubuntu/|g' /etc/apt/sources.list
+        run: |
+            # workaround disabled, splitting the load between azure and arizona.edu to avoid timeouts
+
+            # See reference code in test-build.yml for various sources that may be updated. Enable as needed here.
+            echo "Workaround for sources.list disabled for this workflow"
 
       - name: Update repository
         run: sudo apt-get update
diff --git a/.github/workflows/test-build-mcux-sdk.yml b/.github/workflows/test-build-mcux-sdk.yml
index ee7be2dc1b..66879021da 100644
--- a/.github/workflows/test-build-mcux-sdk.yml
+++ b/.github/workflows/test-build-mcux-sdk.yml
@@ -36,7 +36,11 @@ jobs:
           path: CMSIS_5
 
       - name: Workaround for sources.list
-        run: sudo sed -i 's|http://azure.archive.ubuntu.com/ubuntu/|http://mirror.arizona.edu/ubuntu/|g' /etc/apt/sources.list
+        run: |
+            # workaround disabled, splitting the load between azure and arizona.edu to avoid timeouts
+
+            # See reference code in test-build.yml for various sources that may be updated. Enable as needed here.
+            echo "Workaround for sources.list disabled for this workflow"
 
       - name: Update repository
         run: sudo apt-get update
diff --git a/.github/workflows/test-build-pico-sdk.yml b/.github/workflows/test-build-pico-sdk.yml
index 0ff1e12392..daed6201ef 100644
--- a/.github/workflows/test-build-pico-sdk.yml
+++ b/.github/workflows/test-build-pico-sdk.yml
@@ -39,7 +39,11 @@ jobs:
           git submodule update --init --recursive
 
       - name: Workaround for sources.list
-        run: sudo sed -i 's|http://azure.archive.ubuntu.com/ubuntu/|http://mirror.arizona.edu/ubuntu/|g' /etc/apt/sources.list
+        run: |
+            # workaround disabled, splitting the load between azure and arizona.edu to avoid timeouts
+
+            # See reference code in test-build.yml for various sources that may be updated. Enable as needed here.
+            echo "Workaround for sources.list disabled for this workflow"
 
       - name: Update repository
         run: sudo apt-get update
diff --git a/.github/workflows/test-build.yml b/.github/workflows/test-build.yml
index 285a712c17..ce70d1a000 100644
--- a/.github/workflows/test-build.yml
+++ b/.github/workflows/test-build.yml
@@ -26,10 +26,52 @@ jobs:
           submodules: true
 
       - name: Workaround for sources.list
-        run: sudo sed -i 's|http://azure.archive.ubuntu.com/ubuntu/|http://mirror.arizona.edu/ubuntu/|g' /etc/apt/sources.list
+        run: |
+            # Replace sources
+
+            set -euxo pipefail
+
+            # Peek (what repos are active now)
+            apt-cache policy
+            grep -RInE '^(deb|Types|URIs)' /etc/apt || true
+
+            # Enable nullglob so *.list/*.sources that don't exist don't break sed
+            shopt -s nullglob
+
+            echo "Replace sources.list (legacy)"
+            sudo sed -i \
+              -e "s|https\?://azure\.archive\.ubuntu\.com/ubuntu/?|http://mirror.arizona.edu/ubuntu/|g" \
+              /etc/apt/sources.list || true
+
+            echo "Replace sources.list.d/*.list (legacy)"
+            for f in /etc/apt/sources.list.d/*.list; do
+              sudo sed -i \
+                -e "s|https\?://azure\.archive\.ubuntu\.com/ubuntu/?|http://mirror.arizona.edu/ubuntu/|g" \
+                "$f"
+            done
+
+            echo "Replace sources.list.d/*.sources (deb822)"
+            for f in /etc/apt/sources.list.d/*.sources; do
+              sudo sed -i \
+                -e "s|https\?://azure\.archive\.ubuntu\.com/ubuntu/?|http://mirror.arizona.edu/ubuntu/|g" \
+                -e "s|https\?://azure\.archive\.ubuntu\.com|http://mirror.arizona.edu|g" \
+                "$f"
+            done
+
+            echo "Fix /etc/apt/apt-mirrors.txt (used by URIs: mirror+file:...)"
+            if grep -qE '^[[:space:]]*https?://azure\.archive\.ubuntu\.com/ubuntu/?' /etc/apt/apt-mirrors.txt; then
+              # Replace azure with our mirror (idempotent)
+              sudo sed -i 's|https\?://azure\.archive\.ubuntu\.com/ubuntu/|http://mirror.arizona.edu/ubuntu/|g' /etc/apt/apt-mirrors.txt
+            fi
+
+            # Peek (verify changes)
+            grep -RIn "azure.archive.ubuntu.com" /etc/apt || true
+            grep -RInE '^(deb|Types|URIs)' /etc/apt || true
+            echo "--- apt-mirrors.txt ---"
+            cat /etc/apt/apt-mirrors.txt || true
 
       - name: Update repository
-        run: sudo apt-get update
+        run: sudo apt-get update -o Acquire::Retries=3
 
       - name: Install cross compilers
         run: |
diff --git a/.github/workflows/test-sunnyday-simulator.yml b/.github/workflows/test-sunnyday-simulator.yml
index efcbcc9cc0..bd75627852 100644
--- a/.github/workflows/test-sunnyday-simulator.yml
+++ b/.github/workflows/test-sunnyday-simulator.yml
@@ -17,10 +17,52 @@ jobs:
           submodules: true
 
       - name: Workaround for sources.list
-        run: sudo sed -i 's|http://azure.archive.ubuntu.com/ubuntu/|http://mirror.arizona.edu/ubuntu/|g' /etc/apt/sources.list
+        run: |
+            # Replace sources
+
+            set -euxo pipefail
+
+            # Peek (what repos are active now)
+            apt-cache policy
+            grep -RInE '^(deb|Types|URIs)' /etc/apt || true
+
+            # Enable nullglob so *.list/*.sources that don't exist don't break sed
+            shopt -s nullglob
+
+            echo "Replace sources.list (legacy)"
+            sudo sed -i \
+              -e "s|https\?://azure\.archive\.ubuntu\.com/ubuntu/?|http://mirror.arizona.edu/ubuntu/|g" \
+              /etc/apt/sources.list || true
+
+            echo "Replace sources.list.d/*.list (legacy)"
+            for f in /etc/apt/sources.list.d/*.list; do
+              sudo sed -i \
+                -e "s|https\?://azure\.archive\.ubuntu\.com/ubuntu/?|http://mirror.arizona.edu/ubuntu/|g" \
+                "$f"
+            done
+
+            echo "Replace sources.list.d/*.sources (deb822)"
+            for f in /etc/apt/sources.list.d/*.sources; do
+              sudo sed -i \
+                -e "s|https\?://azure\.archive\.ubuntu\.com/ubuntu/?|http://mirror.arizona.edu/ubuntu/|g" \
+                -e "s|https\?://azure\.archive\.ubuntu\.com|http://mirror.arizona.edu|g" \
+                "$f"
+            done
+
+            echo "Fix /etc/apt/apt-mirrors.txt (used by URIs: mirror+file:...)"
+            if grep -qE '^[[:space:]]*https?://azure\.archive\.ubuntu\.com/ubuntu/?' /etc/apt/apt-mirrors.txt; then
+              # Replace azure with our mirror (idempotent)
+              sudo sed -i 's|https\?://azure\.archive\.ubuntu\.com/ubuntu/|http://mirror.arizona.edu/ubuntu/|g' /etc/apt/apt-mirrors.txt
+            fi
+
+            # Peek (verify changes)
+            grep -RIn "azure.archive.ubuntu.com" /etc/apt || true
+            grep -RInE '^(deb|Types|URIs)' /etc/apt || true
+            echo "--- apt-mirrors.txt ---"
+            cat /etc/apt/apt-mirrors.txt || true
 
       - name: Update repository
-        run: sudo apt-get update
+        run: sudo apt-get update -o Acquire::Retries=3
 
       - name: Install 32-bit libc
         run: |
diff --git a/.github/workflows/test-wolfhsm-simulator.yml b/.github/workflows/test-wolfhsm-simulator.yml
index 100429af23..2396e4b722 100644
--- a/.github/workflows/test-wolfhsm-simulator.yml
+++ b/.github/workflows/test-wolfhsm-simulator.yml
@@ -34,7 +34,11 @@ jobs:
           submodules: true
 
       - name: Workaround for sources.list
-        run: sudo sed -i 's|http://azure.archive.ubuntu.com/ubuntu/|http://mirror.arizona.edu/ubuntu/|g' /etc/apt/sources.list
+        run: |
+            # workaround disabled, splitting the load between azure and arizona.edu to avoid timeouts
+
+            # See reference code in test-build.yml for various sources that may be updated. Enable as needed here.
+            echo "Workaround for sources.list disabled for this workflow"
 
       - name: Update repository
         run: sudo apt-get update