Hi All
I struggled with setting up a Raspberry Pi 4 "boot from SSD" system. I now have 4 "systems" running on Ubuntu Arm64 20.10 with the X825 SSD board, X735 power board enclosed in a X825-C6 case with momentary switch.
I have documented the process I used from updating the bootloader to installing ubuntu 20.10 in this document:
https://handcraftedsoftware.org/download/Pi_boot_from_SSD_public_v1.0.pdf
You are welcome to download and use. Any comments can be emailed to be.
rgds
Greg