* Avoid trying to boot non-existing kernel image in fail-over case
The A/B update system automatically switches to the other boot slot when
booting fails. However, in a fresh installation, only boot slot A
exists. If booting fails three times (e.g. if somebody plugs out power
before the slot can be marked as good), then the system switches to boot
slot B which does not contain a kernel image yet. Avoid trying to boot
the non-existing kernel image.
With this change, if slot B is empty U-Boot will restore both slots to 3
attempts and retry booting from slot A on next reboot:
```
Trying to boot slot B, 2 attempts remaining. Loading kernel ...
** Unrecognized filesystem type **
No valid slot found, resetting tries to 3
storing env...
```
Co-authored-by: Pascal Vizeli <pascal.vizeli@syshack.ch>
* Fix N2+ boot by disabling USB enumeration
On some devices USB enumeration in U-Boot seems to freeze:
starting USB...
Bus usb@ff500000: Register 3000140 NbrPorts 3
Starting the controller
USB XHCI 1.10
scanning bus usb@ff500000 for devices... <freeze>
We don't use USB currenty in the U-Boot script, disable it for now.
* Disable USB enumeration on all ODROID devices
After running HAOS on my ODROID N2+ several hours I see freezes and
sometimes stack traces which point to a problem in CPU frequency
scaling. This crash seems not to appear on Hardkernel's 18.04 Ubuntu
stable release. However, Hardkernel's Ubuntu uses the performance
governor. Use the performance governor as well to avoid crashes on N2+.
* Add ODROID-N2+ support
Add ODROID-N2+ support with the new SoC revision c. Extend the U-Boot
script: Assume ODROID-N2 if the SoC revision is "a" (there are only "a"
revision SoCs on ODROID N2) and assume N2+ otherwise.
Currently using overclock mode as proposed in the upstream kernel patches.
* Update hassos-hook.sh
Co-authored-by: Pascal Vizeli <pascal.vizeli@syshack.ch>
