Hi Jerome,

>> Thank you for the instructions, I managed to successfully boot the latest
>> mainline tree on the Hikey960. Full log in attachment.
>> And even the poweroff sequence looks fine to me.
> 
> Nice.
> 
>> Could you please try to follow the following steps and verify that it works for
>> you as well?
>>
>> 1. Download op-tee version 3.7.0.
>> 2. Enter the linux directory and add the remote
>> git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
>> 3. Rebase the 3.7.0 branch kernel of linux master.
>> 4. Build and Flash op-tee.
>>
>> It should boot and have no issues on init.
> 
> [Unfortunately, it doesn't work for me. The board still hangs (or
> rather, loops) on /init. I'm puzzled at this point... What could be
> wrong with my setup? Do we have different board revisions maybe?
> 

So my board is an Hikey960 ver.B and I am running the latest UEFI firmware.

Some useful links:

[1] https://snapshots.linaro.org/reference-platform/components/uefi-staging/
[2]
https://github.com/96boards-hikey/tools-images-hikey960/blob/master/README-flash-uefi.md

> ...]
> 
> Now that's embarrassing :-/ I decided to re-build everything once again,
> but *without ccache* this time. Guess what? Kernel v5.4 boots fine :-O
> and master too.
> > I used to trust ccache blindly, until I discovered a bug which has
> caused me some trouble for quite some time [1]. After upgrading I
> thought all would be good again, but apparently not... That is quite
> annoying! :-/
> 
> Would you recommend against using ccache for kernel development?
>

I never use ccache for kernel development.

> Anyway, thank you guys for your valuable help. I feel ashamed for
> wasting your time troubleshooting a non-bug... but at least it wasn't in
> vain.
>

Nothing to be embarrassed of, I am curious as well now to know what is going on
with your setup :)

> [1] https://github.com/ccache/ccache/issues/136
> 
>> What I noticed is that the optee
>> provided kernel is not a 5.1 but a 5.1 plus some patches.
> 
> True, but nothing really important. A vanilla kernel is supposed to work
> fine including most of the OP-TEE stuff (except for some very specific
> "secure data path" code which depends on the presence of a special ION
> heap).
> 

Ok, I thought it was worth mentioning.

> Thanks,
> 

-- 
Regards,
Vincenzo