Tried to repack the ISO with modified isolinux.cfg. Since the errors seem to be connected to i915 driver, I added kernel parameter video=SVIDEO-1:d, i915.enable_psr=0, i915.force_probe=*.
Tried other OS-Installers. All boot without problems. Even Fedora 35, which seems to be very close to Qubes 4.1 installer.
Ventoy boot? I did not try it myself but it is very popular with i2p users. You can get it at tracker2.postman.i2p maybe some other places. The description is english if you follow the link.
There are also two more HCL reports running R4.1 on T430 using either the Lenovo BIOS or coreboot/SeaBIOS. So don’t give up! The evidence is overwhelming that it works on your machine. All of the reporters had no issue in installing it.
First step: is this a NitroPad? … if so, maybe contact them for support?
I do not think that is the case. If I understand you correctly you build the T430 yourself / did not buy from Nitrokey and then just flashed their firmware – correct?
Do you have a hardware programmer and feel comfortable doing this? I am happy to send you my ROM file for a quick check. If it works, you might want to compile/build one yourself.