Odroid N2, Booting DietPi USB SSD through Petitboot, “Cannot read /tmp/…_boot_dtb_”

Troubleshooting
1

Creating a bug report/issue

[*] I have searched the existing open and closed issues

Required Information

  • DietPi version | 9.20.1
  • Distro version | trixie
  • Kernel version | Linux odroid 6.12.61-current-meson64
  • Architecture | arm64
  • SBC model | Odroid N2 (aarch64)
  • Power supply used | 12V 2A FULLPOWER ICP30-120-2000
  • USB SSD used | 174c:55aa ASMedia, LITE-ON 128GB SATA SSD
  • SD card used | SanDisk Ultra 16GB

Additional Information (if applicable)

  • Can this issue be replicated on a fresh installation of DietPi? Yes.

Steps to reproduce

  1. Download DietPi_OdroidN2-ARMv8-Trixie.img.xz
  2. Flash to USB SSD with balenaEtcher
  3. Switch to SPI boot (Petitboot) on the Odroid N2
  4. Plug USB SSD in and Turn on

Expected behaviour

  • Boot to DietPi directly from USB SSD through Petitboot

Actual behaviour

  • “Cannot read /tmp/usb0_usr_var_petitboot_mnt_dev_sda1__boot_dtb_”

Extra details

Petitboot status log:

  • [sda1] Processing new Disk device
  • [sda1] Parsed U-boot script from /boot/boot.scr
  • [sda2] Processing new Disk device
  • Booting NO LABEL
  • Loaded kernel image from file:///usr/var/petitboot/mnt/dev/sda1/boot/vmlinuz-6.12.61-current-meson64
  • Loaded initrd from file:///usr/var/petitboot/mnt/dev/sda1/boot/initrd.img-6.12.61-current-meson64
  • Loaded dtb from file:///tmp/usb0_usr_var_petitboot_mnt_dev_sda1__boot_dtb_
  • Performing kexec load
  • Cannot read /tmp/usb0_usr_var_petitboot_mnt_dev_sda1__boot_dtb_
  • Boot cancelled

Have tried with Petitboot version 20220317 and 20231218

Have tried with pb-usbquirks command in Petitboot

Have tried with SD Card and the result is similar: “Cannot read /tmp/mmc1_usr_var_petitboot_mnt_dev_mmcblk1p1__boot_dtb_”

Any idea why this is happening?

2

Ok, I managed to boot directly to USB SSD through Petitboot.

The Petitboot default paths for Kernel, Initrd, and Device tree are wrong..

I changed it to:

  • Kernel: /boot/vmlinuz-6.12.61-current-meson64
  • Initrd: /boot/initrd.img-6.12.61-current-meson64
  • Device tree: /boot/dtb/amlogic/meson-g12b-odroid-n2.dtb

It boots flawlessly after changing those paths.

However, It went back to the defaults every time it reboots.. And I needed to edit those path manually every time..

How to make those paths permanent in Petitboot?

Looking at Petitboot status log, it said: “Parsed U-boot script from /boot/boot.scr”

Maybe we could change the defaults in boot.scr? Any pointers how to do that?

3

Where did you made these changes? In the petitboot menu?

To make it permanent you need to edit boot.cmd and compile it into boot.scr

4

Yes, I made the changes manually in Petitboot menu.

I found another way to make those paths permanent. Petitboot actually looks for grub.cfg file!

So I just made /boot/grub/grub.cfg file:

menuentry "DietPi” {
  linux /boot/Image root=/dev/sda1 rootfstype=ext4 rootwait console=tty1 consoleblank=0 coherent_pool=2M ubootpart= fsck.repair=yes net.ifnames=0
  initrd /boot/initrd.img
  devicetree /boot/dtb/amlogic/meson-g12b-odroid-n2.dtb
}

That’s it..

Petitboot will pick the entry automatically and boots directly from USB SSD!

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5

Oh, I figured out why it’s happening.. The “fdtfile” was not set in boot.scr …

I just added a single line in /boot/boot.cmd, below “# Load addresses”:

setenv fdtfile "amlogic/meson-g12b-odroid-n2.dtb"

Then recompile it with:

mkimage -C none -A arm64 -T script -d /boot/boot.cmd /boot/boot.scr

It now boots correctly, without needing any extra config file.

edit:

Or even simpler.. Just add below line in dietpiEnv.txt

fdtfile=amlogic/meson-g12b-odroid-n2.dtb

Without needing to recompile.. Lol..

Note: On fresh install, if using the dietpiEnv.txt for setup, we’ll need to manually input the paths in Petitboot menu first. Only on the first boot. DietPi will copy the dietpiEnv.txt to /boot after that first boot:

Device: (*) sda1 ["UUID"]
Kernel: /boot/vmlinuz-6.12.61-current-meson64
Initrd: /boot/initrd.img-6.12.61-current-meson64
Device tree: /boot/dtb/amlogic/meson-g12b-odroid-n2.dtb
1 Like