If you have an Odroid C2 (and possibly others) that fails to reboot - here's your fix.

[Javelin]

EDIT: After discussion with a few users, to avoid the issue of having this modification wiped out by a future DTB update and create the unfortunate scenario where the /boot/armbianEnv.txt requests to load a DTB which no longer exists, it's a lot simpler to overwrite the original DTB thus keeping the naming identical. If the DTB gets overwritten by an update then the reboot functionality may just revert to the no-reboot behavior until the fix is re-applied to the newer DTB.

 

The problem lies in the SDCARD signals not being in the right state for a reboot. To solve this we will de-compile the DTB in /boot/dtb/amlogic/meson-gxbb-odroidc2.dtb to create a source version (DTS), modify it, and re-generate the new DTB with the same name. The board will need to be re-started to load-in the new DTB after which the following reboots should be automatic.

 

1) Back-Up everything - if the DTB is somehow not at the right place or the 1 character editing goings wrong there's probably a way to recover from the u-boot console but I haven't explored that.

 

2) Go To:

• /boot/dtb/amlogic
• ls -al  (you will see your meson-gxbb-odroidc2.dtb which is hardcoded in the bootloader as the DTB to load)

 

3) Convert to a source file by doing:

• dtc -I dtb -O dts -o meson-gxbb-odroidc2.dts meson-gxbb-odroidc2.dtb  (you will now have a new DT Source file meson-gxbb-odroidc2.dts)

 

4) Edit:

• vi meson-gxbb-odroidc2.dts
• find the entry TF_IO
• look for the line gpios = <0x38 0x03 0x00>;
• the hex number in red is to be changed from 0x00 to 0x06 (what this does is set the SDCARD in a mode to be ready to boot by allowing the resistor pull-down to enable the VDDIO Regulator to go to 3.3V which is the proper boot voltage)
• save, exit

 

5) Return the DTS file to a new DTB file (which is the only format accepted by the bootloader). We will copy the original DTB to another name and overwrite the original:

• cp meson-gxbb-odroidc2.dtb meson-gxbb-odroidc2-ORIGINAL.dtb
• dtc -O dtb -o meson-gxbb-odroidc2.dtb meson-gxbb-odroidc2.dts
• many warnings will be emitted, they can be safely ignored

 

6) No changes need be performed to /boot/armbianEnv.txt (ie. the 'fdtfile=' directive) as the DTB file with the expected naming will be loaded except now it has the TF_IO mod.

 

7) Now you will reboot - THIS WILL SHUTDOWN BUT WILL NOT REBOOT AUTOMATICALLY BECAUSE THE NEW DTB IS NOT ACTIVE YET.

 

8 ) Do a Power Reset to bring-up the board and load the new DTB.

 

9) Now if you do a reboot you will finally get a proper reboot sequence.

 

 

Edited March 12, 2023 by javelin
Correction to procedure

[dev001]

I'm using Armbian_23.02.1_Odroidc2_jammy_current_6.1.14_xfce_desktop. I followed you instructions and the system keeps continuously rebooting. Unfortunately the photo is not very clear

[Javelin]

I'll download your OS and give it a try to see if I can reproduce.

 

- this is off an sdcard?

- a better log would be great

- to be sure, when your board doesn't reboot you would get this continuously?

bl31 reb▒GXBB:BL1:08dafd:0a8993;FEAT:EDFC318C;POC:3;RCY:0;EMMC:800;NAND:81;SD:800;USB:8;LOOP:1;EMMC:800;NAND:81;SD:800;USB:8;LOOP:2;EMMC:800;NAND:81;SD:800;USB:8;LOOP:3;EMMC:800;NAND:81;SD:800;USB:8;LOOP:4;EMMC:800;NAND:81;SD:800;USB:8;GXBB:BL1:08dafd:0a8993;FEAT:EDFC318C;POC:3;RCY:0;EMMC:800;NAND:81;SD:0;READ:0;CHK:0;

 

[dev001]

The armbian image was written to an eMMC card. Now that I read your posting more closely, you were using an SDCARD. I'm assuming that would not be the same.

[dev001]

If my odroid-c2 keeps rebooting, where do I look for log info?

[Javelin]

Quote

If my odroid-c2 keeps rebooting, where do I look for log info?

 

You'd need to use a USB serial (TTL) board and connect the serial console connector on the board, then use Putty as a terminal and capture there. Unfortunately I don't have an eMMC, also this kind of storage boots slightly differently and these low-level changes would probably need to be done differently.