Re: Issue found when porting to new device.

Hi Vicente,

[Copying the U-Boot Odroid GO2 maintainers]

On Sun, Aug 2, 2026 at 1:35 AM Vicente Bergas <[email protected]> wrote:
>
> Hi,
> i am porting u-boot to a new device:
> https://handhelds.wiki/R36S_Handheld_Wiki
>
> Given the similarity with ODROID_GO2, i've based my efforts on it and
> all goes fine up to the very last step: jumping from u-boot to linux.
>
> In the file arch/arm/cpu/armv8/transition.S there is a call to
> armv8_switch_to_el2_m which is supposed to jump into linux, but it
> doesn't.
>
> I've added some debug prints around it (see patch below) and it prints
> the first message:
> "before switch from EL3 to EL2"
> but it does not print either of the messages after.
>
> As another test, i've tried to replace
> armv8_switch_to_el2_m x4, x5, x6
> to
> br x4
> and then it indeed switches to linux, but then linux crashes, prints a
> trace and reboots, that is, it doesn't like running from EL3.
>
> Please, can somebody help here?

Are you using a recent ARM Trusted Firmware?