No issues with SATA hat on Armbian. Boot still uses the SD to get going, then everything else runs from a drive on SATA. Install to SD or EMMC and then use the Armbian utility to install to SATA.
I'm using Friendly OS currently as it supports hardware video acceleration in Chrome, where Armbian does not. The Bluetooth and analogue sound are also less hassle. BUT, it does not move to SATA - or I have not found out how.
The power button works in both OS. This will be handy if you want a "power failure organised shutdown". 3 pin CPU power management devices exist to do this. I have on Class D amps to stop power down thumps. The shutdown speed of this board is probably less than 1/2 sec, so probably do-able. e.g. MCP121 plus a few resistors.
Poor laptop snuggled in it's bag the last few weeks as the M4 is doing everything I want right now. :-)