Well, looks like you skipped the documentation specifically created for this update: Firmware Update v1.4+ — Nitrokey Documentation and the part which says:
Never try updating your NitroPad using the -maximized image, if you do not know exactly what you are doing!
Just as an additional warning, the releases page on Github says in bold:
If you try to update your Nitropad from a running system using a
-maximized image, YOU WILL BRICK YOUR NITROPAD.
Although, if the
.npf does not work, it looks like your Nitropad was not on version 1.3.1 before, will add a hint for that on both pages.
The good news is: your Nitropad has only a bricked firmware now and all the other stuff is still there and fine, please write an e-mail to firstname.lastname@example.org together with your order reference (SOxxxxxxx) and we’ll find a solution.
edit: oh I see you’ve already done that. Can I kindly ask you to not do multi-channel spamming of the same issue? This generates additional efforts and will not accelerate handling the process, thanks…