Sdm for CM4 (eMMC) boot

[martinkooij]

Hi,

Thanks for your amazing tools! The customizing works great (I have had some wishes for bootconfig, but I will contribute back on that with a PR, I promise!). So 90% of what I want is solved, I need some help, insight for booting my CM4.

Setup: I have a raspi Baseboard with CM4 on it and eMMC, no SD card. II mount the a jumper on the boot pin on the baseboard. I then use rpiboot to prepare the eMMC for flashing as advised by the documentation for CM4 modules. . I then see a /dev/sdb with /dev/sdb1 for bootfs, and /dev/sdb2 for rootfs. I unmount the /dev/sdbx partitions and use sdm --burn ... (all code below) .

After that: I remove the burn eMMC jumper from the Baseboard, reapply power and boot normally. This works perfectly with an image with limited customization. All seems OK. It always works if I keep piwiz and interactively enter some nonsense in there, after that I can login with the configured user from the customization. However, when I remove piwiz from the prepared image (with plugin disable piwiz), it gets stuck in the very beginning after boot. and goes silent Also the serial connection is silent.

I have been fighting, but clearly am too much of a beginner when it amounts to booting raspberri pi's, and can't get this resolved. Two questions: would it work in the end, or am I on a hopeless journey? And if so where should I look for solutions to continue the journey? I love the sdm tools to much to just give up here, and would be greatly helped if I got this last step working.

Thanks for shedding some light on my issue. Code below.

---

Working on a x86 ubuntu linux host. Installed rpiboot and sdm. Dowloaded 64 bit RaspiOS lite, bookworm.

customize image script:

sudo sdm --customize \
    --plugin user:"adduser=myuser|password=mypassword" \
    --plugin disables:"piwiz|bluetooth" \
    --expand-root \
    --regen-ssh-host-keys \
    --plugin bootconfig:"dtoverlay=imx708,cam0" \
    --plugin raspiconfig:"boot_behaviour=B1" \
    --plugin serial:enableshell \
    --restart  \
    --extract-log /home/martinkooij/dev/EXTRA/CM4 \
    raspi.img

burn script:

sudo sdm --burn /dev/sd${DEVICE} \
        --hostname camerapi \
        --expand-root \
        --noreboot \
        raspi.img 

burn output

* Start Burn
> Burn 'raspi.img' (2,8GB, 2,6GiB) to '/dev/sdb'...
> Burn command line: /usr/local/bin/sdm --burn /dev/sdb --hostname camerapi --expand-root --noreboot raspi.img
> dd command: dd if=raspi.img of=/dev/sdb status=progress bs=16M iflag=direct
2281701376 bytes (2,3 GB, 2,1 GiB) copied, 1 s, 2,3 GB/s
164+1 records in
164+1 records out
2759852032 bytes (2,8 GB, 2,6 GiB) copied, 601,712 s, 4,6 MB/s
> dd Copy completed
> Set new disk ID 'b8bc1801' on '/dev/sdb'
Disk identifier changed from 0xd9c86127 to 0xb8bc1801.

The partition table has been altered.
Calling ioctl() to re-read partition table.
Syncing disks.
> Disk ID 'b8bc1801' set successfully with sfdisk
* Mount device '/dev/sdb'
mount: /dev/sdb2 mounted on /mnt/sdm.
mount: /dev/sdb1 mounted on /mnt/sdm/boot/firmware.
% sdm will use qemu 'aarch64'
% sdm will use systemd-nspawn on this 64-bit x86-64 host
  Retry the command with --chroot if this fails
umount: /mnt/sdm/boot/firmware unmounted
umount: /mnt/sdm unmounted
> Expand Root: Expand root partition 'sdb2' (ext4) on device '/dev/sdb' from (2,2GB, 2,1GiB) to 
  (30,7GB, 28,6GiB)
* Mount /dev/sdb to resize the root file system
* Mount device '/dev/sdb'
mount: /dev/sdb2 mounted on /mnt/sdm.
mount: /dev/sdb1 mounted on /mnt/sdm/boot/firmware.
* Resize the ext4 root file system
% (Ignore 'on-line resizing required' message)
resize2fs 1.46.5 (30-Dec-2021)
Filesystem at /dev/sdb2 is mounted on /mnt/sdm; on-line resizing required
old_desc_blocks = 1, new_desc_blocks = 2
The filesystem on /dev/sdb2 is now 7500791 (4k) blocks long.

> Set MBR rootfs partition ID 'b8bc1801' in cmdline.txt (was d9c86127)
> Set MBR partition Disk IDs in fstab
> Disable unneeded RasPiOS firstboot service and /etc/init.d/resize2fs_once
> Disable regenerate_ssh_host_keys/sshd-keygen service(s); sdm FirstBoot will run it instead
> Set hostname 'camerapi'
> First System Boot Custom Boot Scripts disabled
> First System Boot automatic restart disabled
* Burn Completed
> Burn elapsed time: 00:10:12
umount: /mnt/sdm/boot/firmware unmounted
umount: /mnt/sdm unmounted
* Storage '/dev/sdb' is ready

then remove power and jumper. Reapply power to boot.

brcm-pice fd500000.pice: link down
e2fsck 1.47.0 (5-Feb-2023)
rootfs: clean, 61850/1821008 files, 596315/7500791 blocks
[............. deep silence on both keyboard (via USB) and serial., no progress also waited >1 hour...........]

[gitbls]

I don't have a CM4 or CM5 at the moment. I'll have to do some research into this to see what I can dig up. It's curious that e2fsck runs when you boot, since the file system was expanded during burn (--expand-root). Stay tuned....

[gitbls]

Before I spend any more time on this, can I ask you to please review the logs from the customize operation?

I took an unmodified 2025-05-13-raspios-bookworm-arm64-lite.img and customized it using your exact script. At the end of the customization run I got this on the console:

* Phase 1 post-app installation/configuration
> Start 'apt upgrade'
> IMG '2025-05-13-raspios-bookworm-arm64-lite.img' has 228564 1K-blocks (0.2GB, 0.2GiB) free at start of 'apt upgrade'
> IMG '2025-05-13-raspios-bookworm-arm64-lite.img' has 25072 1K-blocks (0.0GB, 0.0GiB) free at end of 'apt upgrade'
!!!
% IMG '2025-05-13-raspios-bookworm-arm64-lite.img' is 99% full
% Review /etc/sdm/apt.log in the IMG for insufficient disk space errors
% If needed use --extend --xmb nnnn with --customize to create more space in the IMG
% Customization terminated due to low disk space condition
!!!
> IMG '2025-05-13-raspios-bookworm-arm64-lite.img' has 25072 1K-blocks (0.0GB, 0.0GiB) free at end of Phase 1 image customization
!!!
% IMG '2025-05-13-raspios-bookworm-arm64-lite.img' is 99% full
% Review /etc/sdm/apt.log in the IMG for insufficient disk space errors
% If needed use --extend --xmb nnnn with --customize to create more space in the IMG
% Customization terminated due to low disk space condition
!!!
umount: /mnt/sdm/boot/firmware unmounted
umount: /mnt/sdm unmounted

Please review your customization log to see if you didn't notice a similar disk space full error.

If you did, you can add --extend --xmb 2048 which will ensure there's plenty of space in the IMG's rootfs. Looks like maybe even 512 would work, but best to over-provision until you get a better feeling for what else you'll be stuffing into the IMG.

If you did NOT receive this error, then I'm going to need to see the history file from your customize run. You can post it here, or if there's confidential information in it you can email it.

[martinkooij]

^^^^ And that was it!!!

It now went through first boot without problem. I am sorry I missed that. I was so set on expecting the boot would fail.
At least we know. It works with CM4!

Thanks for your help.

[gitbls]

Excellent! You're not the first person to miss that, so I guess I'm going to have to make it MUCH more noticeable 🤣