Hi there. I'm having the same problem this guy had, but his fix isn't working for me. I've got a P67A-G45 running 1.J0 (as of today). It seems that no matter what I do, I can't update from the 1.x series of FW to the 5.x series.
I've tried the windows-based installer, live update, m-flash, and am now trying the flash tool in this thread. The contents of the freshly formatted 8gb USB stick are as shown in the attached screenshot. I pulled that .554 file from this thread:
https://forum-en.msi.com/index.php?threads/p67a-g45-bios-not-updated.183345/page-2 But, am hitting the same issue with any .5xx file I've tried. Every time I boot to the USB stick and run startup.nsh, I get the "too many bios files" message and there's nothing I can do from there. I know it's detected the right drive in which to look, as I'm able to verify the contents of the USB stick through the UEFI shell and they match what is shown in the screenshots.
I've followed the instructions in this thread's OP as closely as I can, but for the life of me, I simply can't find any way to ensure SecureBoot is off - though, I suspect I wouldn't be able to boot to the USB stick in the first place if it was. Else, I've done everything in this guide and I'm stumped. I'm trying to do a cost-effective upgrade of my son's PC without breaking the bank, and updating the firmware on the board is required for the chip and gpu I want to give him.
Any ideas where to go from here?