Hi Everyone,
I managed to have it booted off the SD card only without FEL fiddling (also because my A-to-A OTG cable was dumb so I've soldered a UART and get on there trying to dodge the hardcoded protected boot on eMMC by playing with u-boot and tricking it with DTB hacks forcing an internal eMMC disable in favor of SD boot.)
I've ultra simplified the procedure for mere mortals:
1- Flash Pine64 Armbian image on an SD card
2- Flash the "magic 1st Magabyte" (dd brutally the first meg)
3- Insert the SD card in your Remix Mini
4- Boom
The stupid part is that I've done this in a 24 hours rush and kind of tried of backtrack what I did to make it happen... I'm not able to reproduce it but I have all the notes here:
https://gist.github.com/penzoiders/582bfab2c9265716dd375fb5e7679bcf
if anyone of the deveolpers is interested in this I can ship to the maintainers a couple of units (I have dozens of these used-to-be-ewaste devices).
I'll attach the 1M magic boot sector.
remix_mini_armbian_first_1m_pine64.bin