On 4/20/22 23:07, Fabio Estevam wrote:
From: Fabio Estevam festevam@denx.de
Currently, on i.MX8MN/i.MX8MP (Bootrom version 2) it is not possible to load U-Boot via serial download mode, unless CONFIG_ENV_IS_NOWHERE is selected.
This was noticed before by Adam Ford and fixed on the imx8mn beacon board in commit 2c7ebf7778cf ("imx: imx8mn_beacon: Fix USB booting").
Such commit log states:
"The i.MX8M Nano can boot over USB using the boot ROM instead of adding extra code to SPL to support USB drivers, etc. However, when booting from USB, the environment doesnt' know where to load and causes a hang. Fix this hang by supporting CONFIG_ENV_IS_NOWHERE=y. It only falls back to this condition when booting from USB, so it does not impact MMC booting."
I suspect this happens because
arch/arm/mach-imx/imx8m/soc.c env_get_location()
contains " ... default: return ENVL_NOWHERE; "
right ?
I wonder what would happen if you were to add:
case USB_BOOT: return ENVL_UNKNOWN;
Maybe that would even work without CONFIG_ENV_IS_NOWHERE=y ?