this started to happen right after I updated kernel to version 4.9.88-1. Previous version, I think it was 4.9.82-1+deb9u3, worked just fine. This machine strictly follows Debian stable + updates.
I've the serial cable connected and I don't see any strange kernel message on the console. OTOH I hear the disks spinning down and up again, then u-boot shows up, as if some watchdog is kicking in.
In support of the watchdog theory, if I break in u-boot before any kernel is booted, it stays in u-boot as long as I want. If instead I firstly boot and then reboot manually (before the supposed watchdog kicks in), breaking in u-boot lasts only for few minutes (I didn't take wall time but I suspect it's ~5 minutes minus the time it takes to firstly boot and for me to enter the password again).
I don't have the previous kernel package installed, I downloaded it but I'm a bit afraid to install it, I'm quite sure it would not make in time to install and flash everything before a new watchdog kick.
I've some hopes to find a way to avoid enabling the watchdog, so that I can safely downgrade the kernel version but first a few questions here:
1. how is it possible nobody else has this problem?
2. any experience in disabling the watchdog?
3. maybe I'm missing some watchdog package which properly solves my problem?
4. should I open a new bug for the kernel?
Please help me, this machine is quite important to me.
3B10 0CA1 8674 ACBA B4FE FCD2 CE5B CF17 9960 DE13