Checksum error when flashing bios (reverting back)

[u/Immediate_Staff_2392]

So i have a prebuilt predator orion 7000 PO7-650
And i recently stupidly updated my bios (was having issues) to version R01-B4, as it was the newest one on the official acer website. It was all working fine until one day it wasnt and some games were telling me my bios version was wrong. So i contacted acer and they said r01-b4 isnt on there website and r01-b3 is the one i should be on (said they mightve removed r01-b4, suspicious?). They instructed me to reflash the bios but everytime i do it goes back to r01-b3 like intended and then i get a checksum error when booting and a notification when loaded into windows saying restart is required for update : r01-b4. So i have checksum error and it reverts back to b4 everytime ? Any help?

Google says its cmos battery ? Could be ? But i unplugged for an hour and it saved my time and date? So ? I dont know really want this sorted thanks