diff --git a/.github/workflows/build-clang-doxy.yml b/.github/workflows/build-clang-doxy.yml
index e283030b4..3f31af2c5 100644
--- a/.github/workflows/build-clang-doxy.yml
+++ b/.github/workflows/build-clang-doxy.yml
@@ -61,6 +61,7 @@ jobs:
         with:
           repository: adafruit/Wippersnapper_Boards
           path: ws-boards
+          ref: migrate-4mb-to-esptool
       - name: Install CI-Arduino
         run: bash ci/actions_install.sh
       - name: Install extra Arduino libraries
@@ -141,6 +142,38 @@ jobs:
             echo $content
             echo EOF
           } >> "$GITHUB_OUTPUT"
+      - name: fetch tinyuf2 combined.bin
+        run: |
+          DOWNLOAD_URL=$(curl -s https://api.github.com/repos/adafruit/tinyuf2/releases/latest | \
+          jq -r '.assets[] | select(.browser_download_url | contains("tinyuf2-'${{fromJson(steps.get_board_json.outputs.boardJson).bootloaderBoardName}}'-") and endswith(".zip")) | .browser_download_url')
+          if [ -z "$DOWNLOAD_URL" ]; then
+            echo "Error: Could not find the latest tinyuf2 release for board ${fromJson(steps.get_board_json.outputs.boardJson).bootloaderBoardName}."
+            exit 1
+          fi
+          wget "$DOWNLOAD_URL" -O tinyuf2.zip
+          unzip -o tinyuf2.zip -d .
+
+      - name: move partition and bootloader files for tinyuf2 (to match flash_args)
+        run: |
+          # Copy files where they're expected to make flash_args happy
+          mkdir bootloader
+          cp bootloader.bin bootloader/bootloader.bin
+          mkdir partition_table
+          cp partition-table.bin partition_table/partition-table.bin
+
+      - name: Create new_flash_args file from flash_args with added app bin + output file
+        run: |
+          # Create new_flash_args with esptool parameters first and output file
+          echo "--flash-mode ${{fromJson(steps.get_board_json.outputs.boardJson).esptool.flashMode}}" > new_flash_args
+          echo "--flash-freq ${{fromJson(steps.get_board_json.outputs.boardJson).esptool.flashFreq}}" >> new_flash_args
+          echo "--flash-size ${{fromJson(steps.get_board_json.outputs.boardJson).esptool.flashSize}}" >> new_flash_args
+          echo "-o wippersnapper.${{ matrix.arduino-platform }}.fatfs.${{ env.WS_VERSION }}.combined.bin" >> new_flash_args
+
+          # Append flash_args content to new_flash_args, skipping the first line
+          tail -n +2 flash_args >> new_flash_args
+
+          # Append main app to flash_args file
+          echo "0x10000 wippersnapper.${{ matrix.arduino-platform }}.fatfs.${{ env.WS_VERSION }}.bin" >> new_flash_args
       - name: Check boot_app0 file existence (esp32sx built from core, not-source)
         id: check_files
         uses: andstor/file-existence-action@v3
@@ -156,23 +189,17 @@ jobs:
           ls /home/runner/Arduino/hardware/espressif/esp32/tools/partitions
       - name: boot_app0 file from arduino-cli core
         if: steps.check_files.outputs.files_exists == 'true'
-        run: mv /home/runner/.arduino15/packages/esp32/hardware/esp32/*/tools/partitions/boot_app0.bin wippersnapper.${{ matrix.arduino-platform }}.fatfs.${{ env.WS_VERSION }}.boot_app0.bin
+        run: cp /home/runner/.arduino15/packages/esp32/hardware/esp32/*/tools/partitions/boot_app0.bin wippersnapper.${{ matrix.arduino-platform }}.fatfs.${{ env.WS_VERSION }}.boot_app0.bin
       - name: boot_app0 file from esp32 source bsp
         if: steps.check_files.outputs.files_exists == 'false'
-        run: mv /home/runner/Arduino/hardware/espressif/esp32/tools/partitions/boot_app0.bin wippersnapper.${{ matrix.arduino-platform }}.fatfs.${{ env.WS_VERSION }}.boot_app0.bin
+        run: cp /home/runner/Arduino/hardware/espressif/esp32/tools/partitions/boot_app0.bin wippersnapper.${{ matrix.arduino-platform }}.fatfs.${{ env.WS_VERSION }}.boot_app0.bin
+      - name: Copy boot_app0 file to ota_data_initial.bin (overwrite tinyuf2 boot preference)
+        run: cp wippersnapper.${{ matrix.arduino-platform }}.fatfs.${{ env.WS_VERSION }}.boot_app0.bin ota_data_initial.bin
       - name: Create combined binary using Esptool merge-bin
         run: |
           echo ${{ steps.get_board_json.outputs.boardJson }}
           echo ${{ fromJson(steps.get_board_json.outputs.boardJson) }}
-          python3 -m esptool --chip ${{fromJson(steps.get_board_json.outputs.boardJson).esptool.chip}} merge-bin \
-            --flash-mode ${{fromJson(steps.get_board_json.outputs.boardJson).esptool.flashMode}} \
-            --flash-freq ${{fromJson(steps.get_board_json.outputs.boardJson).esptool.flashFreq}} \
-            --flash-size ${{fromJson(steps.get_board_json.outputs.boardJson).esptool.flashSize}} \
-            -o wippersnapper.${{ matrix.arduino-platform }}.fatfs.${{ env.WS_VERSION }}.combined.bin \
-            ${{ matrix.offset }} wippersnapper.${{ matrix.arduino-platform }}.fatfs.${{ env.WS_VERSION }}.bootloader.bin \
-            0x8000 wippersnapper.${{ matrix.arduino-platform }}.fatfs.${{ env.WS_VERSION }}.partitions.bin \
-            0xe000 wippersnapper.${{ matrix.arduino-platform }}.fatfs.${{ env.WS_VERSION }}.boot_app0.bin \
-            0x10000 wippersnapper.${{ matrix.arduino-platform }}.fatfs.${{ env.WS_VERSION }}.bin
+          python3 -m esptool --chip ${{fromJson(steps.get_board_json.outputs.boardJson).esptool.chip}} merge-bin @new_flash_args
       - name: Zip build artifacts
         run: |
           zip -r wippersnapper.${{ matrix.arduino-platform }}.fatfs.${{ env.WS_VERSION }}.zip wippersnapper.${{ matrix.arduino-platform }}.fatfs.${{ env.WS_VERSION }}.*