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johang / sd-card-images

Scripts to build bootable SD card images with Debian for various single-board computers
https://sd-card-images.johang.se
GNU General Public License v3.0
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Empty /boot partition, kernel and u-boot files in rootfs #19

Closed chschnell closed 1 year ago

chschnell commented 1 year ago

First off, thanks a lot for this impressive work.

I tried to build an image for Banana Pi BPI-M2-BERRY with Bullseye using:

sudo docker run --rm -v /tmp/sd-images:/artifacts sd-images build-boot \
    banana_pi_m2_berry allwinner-v40 bananapi_m2_berry_defconfig arm-linux-gnueabihf

sudo docker run --rm -v /tmp/sd-images:/artifacts sd-images build-debian \
    debian armhf bullseye

Two binary files were created, as expected, I concatenated them using:

zcat /tmp/sd-images/boot-banana_pi_m2_berry.bin.gz \
     /tmp/sd-images/debian-bullseye-armhf-XXXXXX.bin.gz > sd-card.img

After flashing sd-card.img to my SD card the device didn't boot. When inspecting the file systems of both .bin files I noticed that:

  1. /boot partition in boot-...bin.gz is empty
  2. /boot directory in debian-...bin.gz contains kernel and u-boot files
  3. trying to move the files from debian-...bin.gz to boot-...bin.gz failed due to a lack of space in the 32M /boot partition

I then tried the same for a Raspberry Pi Zero 2 W and the final image turned out to be structurally ok (I didn't boot it though): two partitions (vfat and ext4), boot files in vfat boot partition and /boot mount point in ext4 rootfs empty.

Finally I ran another attempt for a Banana Pi BPI-M2-ZERO, but it failed for the same problem my initial attempt (Banana Pi BPI-M2-BERRY) failed, vfat /boot partition is empty.

I also checked your downloadable binaries for the two Banana Pis, same problem (mount them and check yourself).

johang commented 1 year ago

Allwinner images have empty FAT partition by design. The bootloader is written to a space between partition table and the FAT partition. The bootloader then loads boot.scr from /boot in the ext4 partition, which then loads dtb and kernel from the ext4 partition.

Connect to the UART and show what is outputs during boot.

chschnell commented 1 year ago

Thanks for the quick clarification, I knew about the bootloader but it's the first time I come across this file layout.

This time it booted perfectly fine, I was simply too impatient earlier (my monitor didn't get a signal for some time). Found that out after connecting the serial port.

I very much apologize for my blunder, and again thanks a lot for your effort here, love it!