SATA on Rock5B via M.2 E-key_board or USB3_connector

[radrocks]

I want at least 1 SATA (option) on my Rock5B and with 6.1 kernel and a SATA overlay file the M.2 E-key via a Radxa breakout board work. Same board as I ordered for Rock3A, this time no soldering and hacking needed although I need to make a big hole in the Radxa metal case (there are small ones for DSI and CSI). So not nice, but OK, doable for me I guess.

On the other hand, I see EDK2-UEFI and mainline kernel have 2 SATA options, the additional one is shared multi-PHY with USB3 I noticed. What does this mean?

Could I solder/merge a USB3 type-A and a SATA cable, so only the 4 SERDES wires and some GND shielding (in theory) ? Or does such a cable even exist already?
If such a cable, I would not need M.2 E-key and bigger hole in metal case, but just sacrifice 1 USB3 connector slot. The whole setup is 12V based, so 3.5inch HDD driving capable.

[radrocks]

Quick scan of schematics make me think a USB3-SATA soldering could work, however I will go for ‘drill a hole in the case’. (passive) cooling is a must for long kernel compile jobs etc that are long term full load on all CPU cores.

[radrocks]

The white old floppydiskdrive connector is on GPIO 4 and 6, I need that for 5V supply of HDD and maybe some more small things/electronics.
Used 8mm HSS metal drill, in the 5th level of the aluminum about 3 mm spaced and making it square with a metal saw, disassembled and put through the holes.