Unable to run UBoot on PocketBeagle 1

General Discussion
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1

Hello everyone. I’m playing around with an old PocketBeagle board (the first one) and uboot. I’d like to boot into the bootloader, but I’ve been unable to do so.
After create a single FAT32 boot partition on the SD card, I have compiled uboot (with am335x_evm_defconfig) and copied both the MLO and u-boot.img files on it. The device boots but goes in a reset loop, printing the following:

resetting ...
U-Boot SPL 2026.04-rc2-00021-gf9ffeec4bdcf-dirty (Feb 20 2026 - 11:57:23 +0100)
Trying to boot from MMC1


U-Boot 2026.04-rc2-00021-gf9ffeec4bdcf-dirty (Feb 20 2026 - 11:57:23 +0100)

CPU  : AM335X-GP rev 2.1
Model: TI AM335x PocketBeagle
DRAM:  512 MiB
Core:  156 devices, 17 uclasses, devicetree: separate
Could not initialize timer (err -19)

I assume this is a problem with the device tree; I have tried changing the default am335x-evm to am335x-pocketbeagle, to integrate it rather than managing it separately, and I’ve also found this proposed patch which sadly doesn’t seem to help. Can anyone point me in the right direction?

2

How much space did you leave before the first partition? am335x_evm_defconfigcreates a huge uboot, as it contains the device tree for all am335x devices. This means the first partition needs to start later …

3

I am storing u-boot.img in the first partition. I’m trying to use the SD card boot mode rather than raw access.