R U running from eMMC -- If so how?

[talpa]

Yes (not as a DD though)

Mobian (switched to unstable)
(I just like running Debian on everything)

bmaptool from a mobian image on uSD card, but I could also just have used good old dd

Still "need" to convert as much as possible of the FS from ext4 to btrfs...
ext4 seems to have forgotten to implement snapshots (and maybe compression)

I also started by compiling and ensuring I could use rkdeveloptool just in case.

I'm also currently having tow-boot installed as the SPI bootloader

power management seems to be "broken" (as was expected)
And I have seen a reboot from time to time, for instance this evening it rebooted as I plugged in a USB-C dock (have been paying with getting 4K output on it)

Also haven't played with using the modem yet.

I too have a quite nice Samsung phone I hope to retire one day, sure the hardware is great (performance wise , way too many closed source components).
The software not so much, hell will probably have been melted by global warming before it would be possible to run Linux / BSD on it.