BIOS Rollback A26 to A25 for e6420

my Latitude e6420 was working fine with BIOS A26 and Win 7 Pro 64 bit, but an SSD failure due to low battery required reinstalling Windows. Checking updates and drivers tells me that I urgently need to install version A25.

Can I simply rollback from A26 to A25 by flashing the A25 version, which I understand is the highest version appropriate for this laptop.

Please advise.