Bananapi R64 from master: print as much info to debug uart as possible

I have an issue with the bananapi r64 code in the master branch on github:
When I run the image, it's continuously rebooting,
when I run in failsafe mode, it's not.
This happens with both sdcard and snand installs
I can see the uart output (but not write to it, that's due to an incompatible controller), it states "lan1: link is up" and then a few seconds later "lan1: link is down"
After that, a minute or 2 later, the board reboots (without dumping anything to uart).
Is there any way I can make the uart print more info? a recompile, anything else?