Bios Update for Memory not recognized during boot.

[Klaus62]

Hello All, I am looking for a bios update that can solve the problem of memory not recognized at the boot process.
Motherboard is MS-7046 and the bios is Phoenix AwardBios W7046ITH V1.0B9.
I would like to update because the bios does not recognize all the installed memory.
Instead of 4Gb counts to 2.8 Gb. OS system id Debian11 and Xubuntu 18.04.
Tried to google without significant results.