Show if flashrom needs to be used by rpi-eeprom-update in tool output (#4718)

Previously we needed to call rpi-eeprom-update -b to learn if flashrom
must be used (which returned an error in that case) and there was no
info if flashrom update is available. Extend the output of the default
printVersions output to show this information as well, as it's rather
inexpensive to check it and it makes it easier to offer relevant update
entities based on that.

Part of #4631

Author: sairon

buildroot-external/package/rpi-eeprom/0003-rpi-eeprom-update-add-early-checks-for-flashrom-avai.patch

@@ -0,0 +1,113 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Jan=20=C4=8Cerm=C3=A1k?= <sairon@sairon.cz>
+Date: Mon, 18 May 2026 15:47:24 +0200
+Subject: [PATCH] rpi-eeprom-update: add early checks for flashrom availability
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+Add check if flashrom needs to be used before it's actually attempted
+and print the result in the version output, along with flashrom
+availability. This makes it easier to check version and offer available
+updates as Home Assistant update entities.
+
+Signed-off-by: Jan Čermák <sairon@sairon.cz>
+Upstream: not applicable
+---
+ rpi-eeprom-update | 57 +++++++++++++++++++++++++++++++++++++++--------
+ 1 file changed, 48 insertions(+), 9 deletions(-)
+
+diff --git a/rpi-eeprom-update b/rpi-eeprom-update
+index 354344c..82832a8 100755
+--- a/rpi-eeprom-update
++++ b/rpi-eeprom-update
+@@ -78,6 +78,10 @@ ACTION_UPDATE_BOOTLOADER=0
+ ACTION_UPDATE_VL805=0
+ CHECKSUMS=''
+ 
++# Set by checkUpdateMethod: 1 when the current boot device cannot apply an
++# EEPROM update (not booting from SD card and flashrom is not usable).
++UPDATE_BLOCKED=0
++
+ cleanup() {
+    if [ -f "${CHECKSUMS}" ]; then
+       rm -f "${CHECKSUMS}"
+@@ -440,12 +444,9 @@ checkDependencies() {
+ 
+    # Default to off - in the future Raspberry Pi 5 may default to using flashrom if
+    # flashrom is available.
+-   if [ "${AUTO_UPDATE_BOOTLOADER}" = 1 ] || [ -n "${BOOTLOADER_UPDATE_IMAGE}" ]; then
+-      [ -z "${RPI_EEPROM_USE_FLASHROM}" ] && RPI_EEPROM_USE_FLASHROM=0
+-      if [ "${RPI_EEPROM_USE_FLASHROM}" -eq 1 ] && ! command -v flashrom > /dev/null; then
+-         warn "WARNING: flashrom not found. Setting RPI_EEPROM_USE_FLASHROM to 0"
+-         RPI_EEPROM_USE_FLASHROM=0
+-      fi
++   [ -z "${RPI_EEPROM_USE_FLASHROM}" ] && RPI_EEPROM_USE_FLASHROM=0
++   if [ "${RPI_EEPROM_USE_FLASHROM}" -eq 1 ] && ! command -v flashrom > /dev/null; then
++      die "flashrom not found but RPI_EEPROM_USE_FLASHROM is set to 1."
+    fi
+ 
+    FIRMWARE_IMAGE_DIR="${FIRMWARE_ROOT}-${BCM_CHIP}/${FIRMWARE_RELEASE_STATUS}"
+@@ -720,6 +721,41 @@ printVersions()
+       echo "   CURRENT: ${VL805_CURRENT_VERSION}"
+       echo "    LATEST: ${VL805_UPDATE_VERSION}"
+    fi
++
++   echo ""
++   if [ "${RPI_EEPROM_USE_FLASHROM}" = 1 ]; then
++      echo "  FLASHROM: yes"
++   else
++      echo "  FLASHROM: no"
++   fi
++
++   checkUpdateMethod
++   if [ "${UPDATE_BLOCKED}" = 1 ]; then
++      echo "   BLOCKED: yes"
++   else
++      echo "   BLOCKED: no"
++   fi
++}
++
++# checkUpdateMethod is the non-fatal counterpart of findBootFS: it checks
++# whether a pending EEPROM update could actually be applied on this device,
++# without mounting anything or aborting, and records the result in
++# UPDATE_BLOCKED. This lets the version-check output report the boot-device
++# status inline instead of only failing once an update is attempted.
++checkUpdateMethod()
++{
++   if blkid | grep -qE "/dev/mmcblk0p1.*LABEL_FATBOOT.*hassos-boot.*TYPE.*vfat"; then
++      # Booting from the SD card - recovery.bin can be staged on /mnt/boot.
++      UPDATE_BLOCKED=0
++   elif [ -n "${BOOTFS}" ]; then
++      # BOOTFS explicitly provided via /etc/default/rpi-eeprom-update
++      UPDATE_BLOCKED=0
++   elif [ "${RPI_EEPROM_USE_FLASHROM}" = "1" ]; then
++      # flashrom writes the SPI EEPROM directly, no boot partition required
++      UPDATE_BLOCKED=0
++   else
++      UPDATE_BLOCKED=1
++   fi
+ }
+ 
+ findBootFS()
+@@ -729,14 +765,17 @@ findBootFS()
+    # If ${BOOTFS} is not writable OR is not on /dev/mmcblk0 then error because the ROM
+    # can only load recovery.bin from the on-board SD-CARD slot or the EEPROM.
+ 
++   checkUpdateMethod
++   if [ "${UPDATE_BLOCKED}" = 1 ]; then
++      die "rpi-eeprom-update is only available when booting from an SD card or if flashrom can be used."
++   fi
++
+    if blkid | grep -qE "/dev/mmcblk0p1.*LABEL_FATBOOT.*hassos-boot.*TYPE.*vfat"; then
+       # use HAOS default bootfs location if booting from SD card
+       BOOTFS="/mnt/boot"
+-   elif [ -z "$BOOTFS" ] && [ "${RPI_EEPROM_USE_FLASHROM}" = "1" ]; then
++   elif [ -z "$BOOTFS" ]; then
+       # image for flashrom will created in bootfs
+       BOOTFS="/mnt/boot"
+-   elif [ -z "$BOOTFS" ]; then
+-      die "rpi-eeprom-update is only available when booting from an SD card or if flashrom can be used."
+    fi
+ 
+    # If BOOTFS is not a directory or doesn't contain any .elf files then