... So let's just go ahead and help you fix that.
First things first, everything is going to be fine. In good time too, so put some sliced bread in a toaster and by the time its done toasting your access to KAUL will be sorted. You just need to (1) purge the April 2025's DevCerts keystore and KAUL 2.7.37 (KUAL-KDK-1.0.azw2 in our case) from your device, (2) set the date of your K2i to a day that agrees with the old Dev certificate keystore then (3) reload KAUL 2.7.35 (luckily that is still KUAL-KDK-1.0.azw2 for us humble legacy folk).
For your benefit I have attached a binary file (update_k2i_kual_fix.bin) in the zipped folder attached that takes care of the new keystore deletion step and then sets the date to one that is compatible with the old certificates (and KAUL 2.7.35). Drag and drop that onto the root directory of your K2i (follow the standard update procedure from your settings menu to let it do its thing) and you're halfway there.
Your next move is to replace KUAL-KDK-1.0.azw2 in your /documents directory with the one from KAUL 2.7.35 (also in the zipped folder attached). Once that is done, take a beat to step back and breathe in all the fumes from the toaster. If its still working, so are we. If it is not, that's too bad (because this is a K2i helper instructional) and maybe after this works you will make space on your K2i for your toaster's instruction manual.
Now all you need to do is drag and drop the binary that loads in the old certificates (Update_mkk-20141129-k2i-B003_install.bin from the zipped folder) in your root directory and run it as an update. Sorted. Open KAUL. It might throw an error on the first go (it did for me and it even had the audacity to call it an "unexpected error"-- which explains nothing) but who knows you might get lucky and be allowed in first try. If it didn't open KAUL and it threw you that error, slap the same button again to actually open KAUL 2.7.35. It worked for me hey it might work for you.
TL;DR- Update with the update_k2i_kual_fix.bin file from the zip.
- Drop the KUAL-KDK-1.0.azw2 file into your K2i's /documents folder
- Update with the Update_mkk-20141129-k2i-B003_install.bin file from the zip