help! backup for jap ps2 with 8-wire mod chip

You have described a boot method I can't reproduce. What you've said is that you boot with the utility disk by pressing reset twice; you get to the memory card/disk screen (that requires pressing X on my PS2); the disk tray pops out and you replace it with the backup. I can't make that boot any backup. This doesn't make sense to me. At the memory card/disk screen you are past the poitn where a backup can be booted!

On my modchip, I boot with the utility disk, it pops out for 4 seconds during which time I insert the backup made as per Universal Patcher. Then it works.

To find out more, would you do the following? There is a file called SYSTEM on your friend's backup. Open that with NOTEPAD.EXE and let me know what it says. If the filename is something like PBPX_952.01 then it's been patched with Paradox and your own CDs should have worked. In either case, copy then copy the friend's CD with CDRWin without using the Universal Patcher. If that doesn't work then you have a reader/burner problem.

You do read on the same device as you burn, yes?