Pinebook Pro doesn't boot most of the time unless connected via USB-serial!

[nib0]

>>Why does reboot fail even though normal booting from SD works?
>With that PARTICULAR distro, on SD (what is it BTW), since its using its uboot
I'm using a minimal manjaro I've built a few days ago with u-boot 2020.07

>try a different one (the 1st uboot to "get the baton" is the one, all others ignored)
Do you mean I should a try different distro, or a different u-boot? If you're talking about different u-boot versions, where do I find them and how do I install them?
I thought that since manjaro is the distro that the current pinebook pros are shipped with, it would have the best support for the hardware.

>maybe serial cable alters timing slightly??
>I thought it was a bit random?
It is, you're right, but it boots most of the times using the serial cable, and it fails most of the times without.

>I still think mrfixits uboot is the best, updated of course
How can I try it out? Can I mix and match, mrfixits uboot with manjaro?

By the way, if you know of any good absolute beginners tutorial for u-boot, please pass it on.

Thanks once again!