danman

Hi - easiest way i found
 
1) In /etc/systemd/system.conf set\uncomment
(max seconds on H3 you can see in g_timeout in 'dmesg | grep "sunxi_wdt_probe"'.
On H2 'dmesg | grep "watchdog"'.
Its ok to set to 16 - it try to send "pings" every half of seted timer)
 
RuntimeWatchdogSec=16
ShutdownWatchdogSec=10min
 
2) reboot, after it check output of "sudo lsof | grep /dev/watchdog" - if it say about systemd - all work
 
3) (DONT RUN THIS ON PRODUCTION SERVERS) test with fork-bomb with and without
 
P.S. - work ok on H2\H3
 

Armbian_20.05.2_Orangepizero_focal_current_5.4.43.img.xz works without any problem. Thank you
 
___ ____ _ _____ / _ \| _ \(_) |__ /___ _ __ ___ | | | | |_) | | / // _ \ '__/ _ \ | |_| | __/| | / /| __/ | | (_) | \___/|_| |_| /____\___|_| \___/ Welcome to Armbian Focal with Linux 5.4.43-sunxi System load: 1.03 1.49 0.70 Up time: 4 min Memory usage: 30 % of 239MB Zram usage: 19 % of 119Mb IP: 192.168.1.129 CPU temp: 56°C Usage of /: 13% of 7.3G [ General system configuration (beta): armbian-config ] Last login: Fri Jun 5 07:17:01 2020 from 192.168.1.137  

Good news! I have found the BOOTSEL pin on my board I connected my logic analyzer to DI pin on SPI header, shorted one suspected pad and saw signals on my analyzer. Then I made a jumper out of 1.27mm pitch pin header and did some fine soldering.
 
Now the question is, what to load to my SPI flash? Does anybody have a full dump from bpi w2 here?

I wrote a short guide how to recover from wiped boot sector https://blog.danman.eu/zidoo-x8-recovery/

@ShaRose, do you have root access on your original system? Can you try:
dd if=/dev/mem bs=1 skip=32505856 count=74410 of=original.dtb (skip and count are translated from hex to dec)
 
@others Meanwhile I was experimenting with the d/g/r> shell. I'm struggling to make ymodem work in minicom but I have some ideas...

Wow! Really? This might help you with searching then
I'll try Ctrl-Q as soon as I'm home.

Ok guys, am I in the club?
 
Last login: Fri May 31 19:21:18 UTC 2019 on ttyS0 _ _ _ | | __ _| | _____ / | | | / _` | |/ / _ \ | | | |__| (_| | < __/ | | |_____\__,_|_|\_\___| |_| Welcome to ARMBIAN 5.86 user-built Debian GNU/Linux 9 (stretch) 4.9.176-rtd1295 System load: 1.09 0.99 0.56 Up time: 8 min Memory usage: 3 % of 1636MB IP: CPU temp: 46�°C Usage of /: 7% of 15G [ General system configuration (beta): armbian-config ]  
my boot command:
 
usb start && fatload usb 0:1 $kernel_loadaddr vmlinuz && fatload usb 0:1 $fdt_loadaddr dtb && env set bootargs earlycon=uart8250,mmio32,0x98007800 console=ttyS0,115200 noinitrd root=/dev/mmcblk0p1 rootfs=ext4 init=/sbin/init && b2ndbc; bootr  

Hooray! I found the problem, I've had following line in /boot/armbianEnv.txt from some previous experiments:
 
machid=1029 All cores are detected correctly after removing it. @Igor thank you for support.