I have one of these M5100, shipping with the R01-A1.
As many here before, I wanted the virtualization feature. Have been looking around for data and tips, and this thread is the more informative. I was hesitating with using a modded BIOS, so thinking I'd play it the safest way I registered ( some 30 USD) on
http://biosagentplus.com/ , downloaded and ran their detection utility (motherboard and BIOS ids) and ordered a BIOS update. What I got was simply the last BIOS provided by ACER on its support site, the R02-B1 , from here for instance:
ftp://ftp.work.acer-euro.com/desktop/aspire_m5100/bios/
so much for 30 US dollar.... Anyway I expected that the reprogramming utility and instructions would be failsafe. They provide the bin file as is and a bootable iso image. I burnt the iso image, which upon reboot loads DOS and autoexec the flashing with AWDFLASH. It didn't work, AWDFLASH exiting with the error:
"The program file's part number does not match with your system."
Searching the online help and faq of biosagentplus.com I found they recomment to force AWDFLASH with the /QI switch.
So I created an USB DOS stick with the latest AWDFLASH and the R02-B1. Boot on it, launch AWDFLASH /PY /CC /CD /SN /QI and /WB (= reprogram BootBlock). I was hesitating about /WB, but in some large BIOS data gets into the bootblock zone, so I was wondering if it is the case with this one, maybe omitting /WB could end in a botched BIOS. And biosagentplus uses that switch. So I went for it.
The flashing went smooth, no warnings, no write errors, and completed with a successful message.
I reset the peecee and .... black screen and silent. Nothing. As others here have experienced with modded bioses.
It's not completely dead because removing memories brings a looping long simple beep. But keyboard shows no activity, and that M5100 doesn't come with floppy, I have none avail. so can't try a blind automated DOS recovery (in case bootblocks are still there...).
I also removed CMOS battery, jumpered on|off the clearing jumper without success.
So there's really something with that M5100 box.
I have ordered a new BIOS PLCC chip programmed with the original R01-A1 to get the peecee living again.