Hey,
I do have exactly the same problem but actually using a ‘tested by team’ HP EX900 M.2 with 120GB. demsg output is exactly the same than in Druid’s case. Tested with Ubuntu, Armbian, Debian both directly connected to the RockPi and with the extension board. Manjaro seems to give a slightly different output only looking for a 12V supply including a driver error exiting also with -110.
Shall I also try with another SSD? What do you recommend for a smaller SPI bootable SSD?
I also found the German FAQ where it is stated that the HP EX900 is exactly the one that doesn’t work. Compare here (German) vs. here (en)
Thanks folks!