modify bios SPD data for hp stream 11-y106ur

[ArtemKuchin]

I have hp stream 11-y106ur whith Insyde H2O bios. I have downloaded the latest bios, decrypted it and found the spd data inside. I want to solder new ram chips. I have 4GBof ram and want to upgrade to 8GB. I already upgraded emmc to 128GB (from 32) and next is CPU (4 core). But RAM is the problem, because it needs SPD data modification in bios.  I don;t know how RSA checks work in this bios. People say that signature is checked at every boot. Maybe it is possible to sign with my own signature? Replace signature? I don't see any hacked bios for this laptop w/o rsa checks. Well, any information and thoughts will be appreciated.

[ArtemKuchin]

btw One strange thing i found in the bios is several bad spd blocks.
I scanned for SPD block using CRC check (SPD has CRC16 XMODEM check) and i found only 3, but when i then searched for starting bytes i have found 2 more SPD block with the same data but incorrect CRC16 checksums. Crazy stuff.

I can modify the spd but then i cannot flash the bios because i cannot sign it.
I could probably using a hardware flasher to write bios data into the spi flash chip, but it has signature check and it will fail. So, i need to disassemble some module inside bios and kill the check. But when module is that?
I could not find the signature inside the bios itself. If i could find i would probably find the address access in the assembly.