Revert to previous boot firmware version

An I²C-related issue has been introduced by updating to the March 24th
version of start_cd.elf/fixup_cd.dat.

Revert to the January 20th version until this is investigated and fixed.

.github/workflows/ci.yml

@@ -99,23 +99,23 @@ jobs:
       with:
         submodules: recursive
 
-    - name: Cache boot files
-      id: cache-boot-files
-      uses: actions/cache@v3
-      with:
-        path: |
-          sdcard/armstub8-rpi4.bin
-          sdcard/bcm2711-rpi-4-b.dtb
-          sdcard/bcm2711-rpi-400.dtb
-          sdcard/bcm2711-rpi-cm4.dtb
-          sdcard/bootcode.bin
-          sdcard/COPYING.linux
-          sdcard/fixup_cd.dat
-          sdcard/fixup4cd.dat
-          sdcard/LICENCE.broadcom
-          sdcard/start_cd.elf
-          sdcard/start4cd.elf
-        key: cache-boot-files-${{ hashFiles(join(env.boot-home, '/Makefile')) }}
+    # - name: Cache boot files
+    #   id: cache-boot-files
+    #   uses: actions/cache@v3
+    #   with:
+    #     path: |
+    #       sdcard/armstub8-rpi4.bin
+    #       sdcard/bcm2711-rpi-4-b.dtb
+    #       sdcard/bcm2711-rpi-400.dtb
+    #       sdcard/bcm2711-rpi-cm4.dtb
+    #       sdcard/bootcode.bin
+    #       sdcard/COPYING.linux
+    #       sdcard/fixup_cd.dat
+    #       sdcard/fixup4cd.dat
+    #       sdcard/LICENCE.broadcom
+    #       sdcard/start_cd.elf
+    #       sdcard/start4cd.elf
+    #     key: cache-boot-files-${{ hashFiles(join(env.boot-home, '/Makefile')) }}
 
     - name: Cache WLAN firmware
       id: cache-wlan-firmware
@@ -134,15 +134,17 @@ jobs:
         key: cache-arm-toolchains-${{ env.toolchain-version }}
 
     - name: Update PATH
-      if: steps.cache-boot-files.outputs.cache-hit != 'true'
+      # if: steps.cache-boot-files.outputs.cache-hit != 'true'
       run: |
         for triplet in arm-none-eabi aarch64-none-elf; do
           echo "$HOME/gcc-arm-${{ env.toolchain-version }}-x86_64-${triplet}/bin" >> $GITHUB_PATH
         done
 
     - name: Download boot files and build ARM stub if not retrieved from cache
-      if: steps.cache-boot-files.outputs.cache-hit != 'true'
+      # if: steps.cache-boot-files.outputs.cache-hit != 'true'
+      # Temporarily patch boot firmware version
       run: |
+        patch -N -p1 --no-backup-if-mismatch -r - -d external/circle-stdlib/libs/circle < patches/circle-44.5-revert-firmware.patch
         make -C ${{ env.boot-home }} firmware armstub64
         cp  ${{ env.boot-home }}/armstub8-rpi4.bin \
             ${{ env.boot-home }}/bcm2711-rpi-4-b.dtb \

CHANGELOG.md

@@ -7,6 +7,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Fixed
+
+- I²C communications failure on MiSTer introduced with newer Raspberry Pi firmware. The previous firmware version has been restored until this is resolved.
+
 ## [0.12.0] - 2022-06-13
 
 ### Added

Makefile

@@ -16,6 +16,7 @@ $(CIRCLE_STDLIB_CONFIG) $(CIRCLE_CONFIG)&:
 	$(CIRCLESTDLIBHOME)/configure --raspberrypi=$(RASPBERRYPI) --prefix=$(PREFIX)
 
 	# Apply patches
+	@patch -N -p1 --no-backup-if-mismatch -r - -d $(CIRCLEHOME) < patches/circle-44.5-revert-firmware.patch
 	@patch -N -p1 --no-backup-if-mismatch -r - -d $(CIRCLEHOME) < patches/circle-44.4-minimal-usb-drivers.patch
 
 ifeq ($(strip $(GC_SECTIONS)),1)
@@ -121,6 +122,7 @@ clean:
 veryclean: clean
 	# Reverse patches
 	@patch -R -N -p1 --no-backup-if-mismatch -r - -d $(CIRCLEHOME) < patches/circle-44.4-minimal-usb-drivers.patch
+	@patch -R -N -p1 --no-backup-if-mismatch -r - -d $(CIRCLEHOME) < patches/circle-44.5-revert-firmware.patch
 	@patch -R -N -p1 --no-backup-if-mismatch -r - -d $(FLUIDSYNTHHOME) < patches/fluidsynth-2.2.7-circle.patch
 
 	# Clean circle-stdlib

patches/circle-44.5-revert-firmware.patch

@@ -0,0 +1,13 @@
+diff --git a/boot/Makefile b/boot/Makefile
+index 6aadb4b..90395d4 100644
+--- a/boot/Makefile
++++ b/boot/Makefile
+@@ -9,7 +9,7 @@
+ #FIRMWARE = master
+ 
+ # Use firmware revision built/committed on: Mar 24 2022
+-FIRMWARE ?= ea4c803c57697aad951a27fcd64c01ef16f9fe7f
++FIRMWARE ?= 827fdd073638fa7b7292d1148fe0af7465111eae
+ 
+ BASEURL = https://github.com/raspberrypi/firmware/blob/$(FIRMWARE)/boot
+