So, trying to get my Iron Man VE code updated.

I got a new game code but during the process of updating/failing, it's wiped the code that was on there.

I am wary that Iron Man Vault Edition code should be used as I have a xx52 ending CPU/Sound Board due to the changes in the USB its built with. (From Stern Bulletin/code update)

I'm using a Bootrom v1.0 which works fine (Bootrom 3.1 is not for this board and doesn't work)

I'm trying an old USB stick now and completely slow formatting it in FAT 32 rather than quick format.

The code verifies OK in the update, flash memory clears OK in the process. But the update quits with error code 1. I can't find anything online saying what that error is exactly.

The update is not zipped and is a binary, extracted on a PC.

I've used a PC to move and format the usb/code file.

I've successfully updated Stern games OK before (TWD, LOTR although they were different boards)

I can't think of anything I've done wrong and am a bit stuck - would welcome suggestions.