On 28 February 2017 at 09:18, H. Nikolaus Schaller <hns@goldelico.com> wrote:

I already had observed that there is some "memory effect" which has
something to do with how fast and in which sequence power is (re)applied
and so far I thought that the Palmas backup (supercap) has something to
do with it.

Ah there's a supercap too? I hadn't even stopped to think about that one...

I've quite often seen strange memory effects, or "bistability" of some sort where it either boots fine (into u-boot at least) repeatedly, or utterly fails (often even without any message on console) repeatedly.

Ah, interesting! I always thought that MLO does not use DRAM at all
because it runs from and within SRAM.

I think it has some config options controlling how much is relocated to DRAM.

Yes, there must be something wrong with warm reset. If I "reboot"
from Linux everything works well, up to Kernel starting... where
nothing happens any more.

I've also noticed that the reset using shoulder button + power button rarely recovers the system from a wedged state (although it seems to work fine if the system is running fine).

Matthijs