Hi all,
I managed to blow FIELD_RETURN fuse on our (closed) i.MX8MN based custom board. Now I want to boot this board using an unsigned bootloader image file but no success. The SPL code starts and downloads remaining u-boot parts via BOOTROM API, but then boot messages stop:
U-Boot SPL 2022.04-00079-ga37bf36a47-dirty (Nov 02 2023 - 14:54:37 +0000)
Normal Boot
WDT: Started watchdog@30280000 with servicing (60s timeout)
Trying to boot from BOOTROM
Find img info 0x&48025a00, size 932
Need continue download 1024
Download 719920, Total size 721456
ROM download finished OK
As can be seen, the unsigned bootloader is able to start on the FIELD_RETURN fused board, but then stops when ATF firmware is going to be executed.
I have enabled the CONFIG_ARMV8_SPL_EXCEPTION_VECTORS setting to workaround the ROM serror issue with ATF firmware (see https://www.mail-archive.com/u-boot@lists.denx.de/msg376429.html).
I can boot that bootloader image to prompt using an unlocked device of that same board:
U-Boot SPL 2022.04-00079-ga37bf36a47-dirty (Nov 02 2023 - 14:54:37 +0000)
Normal Boot
WDT: Started watchdog@30280000 with servicing (60s timeout)
Trying to boot from BOOTROM
Find img info 0x&48025a00, size 932
Need continue download 1024
Download 719920, Total size 721456
ROM download finished OK
NOTICE: BL31: v2.2(release):rel_imx_5.4.47_2.2.0-0-gc949a888e-dirty
NOTICE: BL31: Built : 11:10:34, Dec 9 2022
U-Boot 2022.04-00079-ga37bf36a47-dirty (Nov 02 2023 - 14:54:37 +0000)
CPU: Freescale i.MX8MNano UltraLite Quad rev1.0 at 1200 MHz
Reset cause: POR
Model:
DRAM: 1 GiB
Core: 67 devices, 19 uclasses, devicetree: separate
WDT: Started watchdog@30280000 with servicing (60s timeout)
MMC: FSL_SDHC: 1, FSL_SDHC: 2
Loading Environment from MMC... OK
In: serial@30a60000
Out: serial@30a60000
Err: serial@30a60000
BuildInfo:
- ATF c949a88
Net: eth0: ethernet@30be0000
Hit any key to stop autoboot: 0
u-boot=>
What am I missing to make the (unsigned) bootloader boot to prompt on the FIELD_RETURN enabled board?
Best regards,
Thomas
