Another step further...
so the fuse setting ran, thank you Venturi962! and the programming too.
Two of the fuses seem to be correct the lock one is untouched.
I re-plugged it in and it appeared as a storage device
$lsusb
Bus 003 Device 019: ID 03eb:2045 Atmel Corp. LUFA Mass Storage Demo Application
I then copied the test and measurement bin to the drive and verified if it copied ok.
$cp TestAndMeasurement.bin /run/media/baettig/GPIBUSBBOOT/FLASH.BIN
$md5sum TestAndMeasurement.bin /run/media/baettig/GPIBUSBBOOT/FLASH.BIN
bb6785db41417e20e522b72fcbcfba61 TestAndMeasurement.bin
bb6785db41417e20e522b72fcbcfba61 /run/media/baettig/GPIBUSBBOOT/FLASH.BIN
So I unplugged it and plugged it in one more time, now it should not be visible until it is connected to the GPIB on a TM device...
It reappeared as a drive ...
Unplugging and plugging it into my E3633 power supply (configured as a GPIB device) still doesn't make it change itself to a GPIB interface...
according to the manual on github
"USB enumeration
You might be surprised initially, that the device does not show up in your device manager (or lsusb), when you connect only the USB side. This is a feature, not a bug (really!). Only, if a GPIB device is connected, you can see the device on your PC too."
(I just checked on github and seem to have run into an issue that someone else is at, too:
https://github.com/xyphro/UsbGpib/issues/11 unfortunately without resolve so far...)
I'd be grateful for any hints.