34s flashing cable possible candidate?

[Tugdual]

I found the following cable in a box. I have to confess I can't remember what it was used for but I would suspect it was my old HP Jornada cable though it is written "Belkin" on the USB plug. This cable looks pretty similar to the official 30s flash cable doesn't it?

I couldn't figure out how to open the small box in the middle of the cable, it looks sealed. There is a two positions button in the middle that lits a red or green led.
I would like to reuse this cable to flash the 30s into a 34s but I'm not sure how to proceed from there... Any idea?