There might be a problem with the USB part of the flash drive. If you have a newer computer you could use a regular Ethernet cable to connect to the ps3 directly.
If you have the latest version if Luma installed then updating the official firmware should cause no issues. Maybe someone else can answer your second question.
Do you have a computer to connect to with the Ethernet cable? If you have a newer computer you won't need a crossover ethernet cable. You might try a ftp program on the computer.
I finally modeled and 3d printed the new HDD cages I need in order to build my 2nd NAS. Original ones don't fit the mounting holes on the hdds I'm using. Been sitting on this project for over 2 years smfh
Also another 70TB going in the front mount drive bays of this server. 182tb raw, going to probably use a zfs RAID-Z3 for 3 parity disks, so 140TB usable
I could claw back 14tb by only doing 2 parity disks but I feel like with 13 disks in the RAID I'd be kind of pushing my luck on rebuild time if I encounter a disk failure