Hey, Lixton,
I have this same problem, it seems that there is a special tool that only Line 6 US has access to. I specifically bought a (secondhand) v75 receiver to update the gear, but the tbp12 needs to be v1.03. It does actually say it needs to be v1.03 to do home updates on the guide page in this forum, in red near the top. Unfortunately, I live in Australia, so it's a bit more involved to get one of my favourite guitar tools up to the latest spec.
Hopefully you can make do with rf2 on two units, or just rf1 with three if needed (switching transmitter modes). Hope you found a result anyways.
Joe
