Trying to update old Wisycom MTP41s with FW 1.30.0.P, Bootloader not valid

[Till Roellinghoff]

I guess this have been discussed a few years back, maybe someone can hint me to the forum entry. 

I'm trying to update my older WisyMTP41s with FW1.30.0.P to the last one, but Wisycom manager let me update my Txs only with FW 1.4.XX. I heard its a bootloader problem, but i can't find updates for that. I have installed the old TX Updater, the old Manager 1.1.15 and also the newest version 5.1.0. but so far no clue, how to update the Bootloader that it ca read the newer .xupf FW files. Anyone knows how to do it? Thanks in advance..