[PATCH 1/2] live-vm-common.bbclass: conditionally to add kernel and initrd to efi.img of ISO live

[PATCH 1/2] live-vm-common.bbclass: conditionally to add kernel and initrd to efi.img of ISO live

[Hongxu Jia]

Add var-EFI_ISO_KERNEL, if ${EFI_ISO_KERNEL} != "1", do not add kernel and
initrd to efi.img of ISO live.

For grub-efi's ISO live, the kernel and initrd is not necessary in efi.img,
because grub-efi's bootx64.efi sets `search.file ($cmdpath)/EFI/BOOT/grub.cfg root'
to locate kernel and initrd in ISO live image.

It helps while the size of initrd is big to break the limit of efi.img in which
the filesystem type is FAT

Also clean up ${EFIIMGDIR} before populating

Set EFI_ISO_KERNEL ??= "1" by default which adds kernel and initrd to efi.img
as usual

Signed-off-by: Hongxu Jia <hongxu.jia@windriver.com>
---
 meta/classes-recipe/live-vm-common.bbclass | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/meta/classes-recipe/live-vm-common.bbclass b/meta/classes-recipe/live-vm-common.bbclass
index d90cc67ebc..f087d9e236 100644
--- a/meta/classes-recipe/live-vm-common.bbclass
+++ b/meta/classes-recipe/live-vm-common.bbclass
@@ -48,18 +48,25 @@ efi_populate_common() {
         printf 'fs0:%s\%s\n' "$EFIPATH" "${EFI_BOOT_IMAGE}" >${DEST}/startup.nsh
 }
 
+# Kernel(with initrd) image in efi.img of ISO live
+EFI_ISO_KERNEL ??= "1"
+
 efi_iso_populate() {
         iso_dir=$1
         efi_populate $iso_dir
+
+        rm -rf ${EFIIMGDIR}
         # Build a EFI directory to create efi.img
         mkdir -p ${EFIIMGDIR}/${EFIDIR}
         cp $iso_dir/${EFIDIR}/* ${EFIIMGDIR}${EFIDIR}
-        cp $iso_dir/${KERNEL_IMAGETYPE} ${EFIIMGDIR}
+        if [ "${EFI_ISO_KERNEL}" = "1" ]; then
+                cp $iso_dir/${KERNEL_IMAGETYPE} ${EFIIMGDIR}
+        fi
 
         EFIPATH=$(echo "${EFIDIR}" | sed 's/\//\\/g')
         printf 'fs0:%s\%s\n' "$EFIPATH" "${EFI_BOOT_IMAGE}" >${EFIIMGDIR}/startup.nsh
 
-        if [ -f "$iso_dir/initrd" ] ; then
+        if [ -f "$iso_dir/initrd" -a "${EFI_ISO_KERNEL}" = "1" ] ; then
                 cp $iso_dir/initrd ${EFIIMGDIR}
         fi
 }
-- 
2.25.1

[PATCH 2/2] image-live.bbclass: fix booting EFI ISO live failed

[Hongxu Jia]

In ISO live, if the size of efi.img >= 32MB, and copy EFI application
(bootx64.efi) to efi.img behind of kernel and initrd, UEFI system
could not find EFI application bootx64.efi

In UEFI shell:
...
Shell> ls FS0:\
Directory of: FS0:\
04/05/2011  23:00          12,985,344  bzImage
04/05/2011  23:00 <DIR>         2,048  EFI
04/05/2011  23:00          20,494,696  initrd
04/05/2011  23:00                  26  startup.nsh
          3 File(s)  33,480,066 bytes
          1 Dir(s)

Shell> ls FS0:\EFI
Directory of: FS0:\EFI
          0 File(s)           0 bytes
          0 Dir(s)
...

The fs type of efi.img is FAT, it seems UEFI system only know
first 32MB in efi.img, due to kernel and initrd take the most
disk space, in order to make sure EFI application bootx64.efi could
be detected by UEFI system, copy EFI BOOT and other configuration
first, and then kernel and initrd at last

As comparing, after applying this commit, for the same project,
EFI application bootx64.efi was found
In UEFI shell:
...
Shell> ls FS0:\
Directory of: FS0:\
04/05/2011  23:00          12,985,344  bzImage
04/05/2011  23:00 <DIR>         2,048  EFI
04/05/2011  23:00          20,494,696  initrd
04/05/2011  23:00                  26  startup.nsh
          3 File(s)  33,480,066 bytes
          1 Dir(s)
Shell> ls FS0:\EFI\BOOT
Directory of: FS0:\EFI\BOOT\
04/05/2011  23:00 <DIR>         2,048  .
04/05/2011  23:00 <DIR>         2,048  ..
04/05/2011  23:00             655,360  bootx64.efi
04/05/2011  23:00                 281  grub.cfg
          2 File(s)     655,641 bytes
          2 Dir(s)
...

Signed-off-by: Hongxu Jia <hongxu.jia@windriver.com>
---
 meta/classes-recipe/image-live.bbclass | 19 ++++++++++++++++++-
 1 file changed, 18 insertions(+), 1 deletion(-)

diff --git a/meta/classes-recipe/image-live.bbclass b/meta/classes-recipe/image-live.bbclass
index d2e95ef51c..40ee86b822 100644
--- a/meta/classes-recipe/image-live.bbclass
+++ b/meta/classes-recipe/image-live.bbclass
@@ -211,7 +211,24 @@ build_fat_img() {
 	fi
 
 	# Copy FATSOURCEDIR recursively into the image file directly
-	mcopy -i ${FATIMG} -s ${FATSOURCEDIR}/* ::/
+	fat_source_dirs="$(ls ${FATSOURCEDIR}/* -d)"
+	fat_sources=""
+	for source_dir in $fat_source_dirs; do
+		# Skip kernel and initrd
+		if [ ${source_dir%${KERNEL_IMAGETYPE}} = "$source_dir" -a \
+		     ${source_dir%initrd} = "$source_dir" ];then
+			fat_sources="$fat_sources $source_dir"
+		fi
+	done
+	# Copy EFI BOOT and other configuration at first
+	mcopy -i ${FATIMG} -s $fat_sources ::/
+	# Copy kernel and initrd at last if available
+	if [ -e ${FATSOURCEDIR}/${KERNEL_IMAGETYPE} ];then
+		mcopy -i ${FATIMG} ${FATSOURCEDIR}/${KERNEL_IMAGETYPE} ::/
+	fi
+	if [ -e ${FATSOURCEDIR}/initrd ]; then
+		mcopy -i ${FATIMG} ${FATSOURCEDIR}/initrd ::/
+	fi
 }
 
 build_hddimg() {
-- 
2.25.1

Re: [OE-core] [PATCH 2/2] image-live.bbclass: fix booting EFI ISO live failed

[Ross Burton]

On 28 Mar 2025, at 13:02, hongxu via lists.openembedded.org <hongxu.jia=eng.windriver.com@lists.openembedded.org> wrote:
> 
> In ISO live, if the size of efi.img >= 32MB, and copy EFI application
> (bootx64.efi) to efi.img behind of kernel and initrd, UEFI system
> could not find EFI application bootx64.efi

That sounds very suspicious to me, especially the 32MB limit.  Is this file system being accidentally created as FAT12, which does have a 32MB limit?

Can you try just forcing FATSIZE=“-F 32” to force FAT32 instead of these patches?

Ross

Re: [PATCH 2/2] image-live.bbclass: fix booting EFI ISO live failed

[hongxu]

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Hi Ross,

Forcing FATSIZE=“-F 32” did not work, I also tried to use GPT + FAT partition to instead of MBR + FAT, and still failed

//Hongxu

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