I'm trying to add SLIC 2.1 on a HP 250 G5 laptop with UEFI Insyde bios. I have unpacked the bios update, identified the correct BIN file, did the RW everything, used the Phoenix Tool 2.66 to insert the SLIC file. But I can't flash it. I can't find any InsydeFlash tool that works on this laptop, and trying from recovery does not work becuase the bios comes with a signature file (.s12) that does not match when modified with the Phoenix Tool. When trying to flash from recovery, if I don't include the signature says "no signature found", and if I use the original signature, refuses with the error of "invalid signature". Where I can download a InsydeFlash utility that is able to flash without signature? Or is there a way to generate the RSA signature for the modified bios?
Where is the signature check? Is in the bios itself or only on the flashing software? Is there a chance to flash the modded bios using another software, or using an EEPROM flasher?