Unable to change from UEFI to Legacy Mode

Question

i have a Acer Aspire 5 A515-44 with Windows 10 Pre-installed , but I need for my Car Diagnostic Programs Windows 7. So I decided to work with a Virtual Machine installed Win 7 but the programs won't work and my Car Program Devices won't connect to Win 10 so it doesn't even show up on the Virtual Machine... anyways ,the next option was to install Windows 7 on my second ssd but I can't change from UEFI to Legacy Support or any other options. Boot Mode UEFI is greyed out so I can't even look if there is any other options avaible. Disable Secure Boot doesn't help and I really don't know what to do?? Never had this problem before.

Edit: Installing Windows 7 with Secure Boot Disabled gives me an error in Windows Boot Manager, Error: 0xc00000d

Acer Aspire 5 A515-44 (AMD) -

Not all systems will have compatibility or support for BIOS. It essentially requires the manufacturer to write an emulation layer that sits on top of UEFI and impersonates a BIOS system. It might not be that difficult, but as BIOS is effectively obsolete it should not be a surprise when it is no longer supported. — Mokubai, Mar 25 '21 at 11:02
Windows 7 also should be able to be installed under UEFI Clean install of Windows 7 Pro 64-bit on a UEFI laptop with GPT partition? but you may need to delete partitions on the destination disk and convert it to GPT partitioning first. — Mokubai, Mar 25 '21 at 11:04
Windows 7 supports UEFI. All that should be required is to disable Secure Boot. Using legacy mode isn’t a solution to your problem that would require you to reinstall Windows 10 anyway — Ramhound, Mar 25 '21 at 11:31

score 2 · Answer 1 · answered Mar 25 '21 at 10:58

2

According to the post How to enable Legacy Boot on Aspire A515-54, the solution is to install the latest BIOS version.

You may download the BIOS from Acer at Download Acer support drivers.

answered Mar 25 '21 at 10:58

harrymc

480,290

I have the latest version but it didn't changed anything. My Model is A515-44 , not 54. Don't know why other models can change but my model can't – Caro Mar 25 '21 at 12:02
Also i can't access the Community site from acer , I get this error
Something has gone wrong. We've run into a problem and are unable to handle this request right now. Please check back in a little while.
– Caro Mar 25 '21 at 12:08
(Note: The news have mentioned a successful attack by hackers on ACER servers, which might be why you're unable to connect at the moment.) I know that some manufacturers have models that are without the option of booting into Legacy Mode, so yours might unfortunately be one of them. I suggest that you contact ACER Support to verify this point. – harrymc Mar 25 '21 at 12:19
That's so unlucky ... thank you for the information I will try to contact them as soon as possible – Caro Mar 25 '21 at 12:27
1

Windows 7 64bit supports UEFI but only Class 2 UEFI not Class 3. In Class 3 all devices are UEFI compliant including graphics and there’s no provision to switch to VBIOS. Windows 7 supports UEFI Boot mode i.e. UEFI Boot + GPT partition scheme but still needs graphics in CSM (VBIOS). Whereas in Class 3 it’s GOP. I have no idea what your machine firmware is but as @harrymc says you need to check with your manufacturer. ...Continued – patkim Mar 25 '21 at 14:33
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..Continued. Just in case your device is Class 3 UEFI with absolutely no CSM support, you may just try a third party tool called UEFI Seven https://github.com/manatails/uefiseven This tool simulates legacy INT 10H for graphics and may allow you to install Windows 7 on Class 3 Firmware. Of course results may vary from hardware to hardware and never the less Secure boot must be disabled anyways. – patkim Mar 25 '21 at 14:33
@patkim this seems to be the solution (uefiseven) but my Installation Stucks at Starting Windows ... , even before the installation screen. The Problem has to do with my VGA drivers or something like that. I already contacted the developer of uefiseven and will post my solution if i get it fixed. Thank You – Caro Mar 25 '21 at 15:01

mirh · Answer 2 · 2022-04-14T18:09:02.967

Uefiseven and other hacks are all fine and dandy to workaround official Windows limitations, but alas they still aren't perfect. So for the sake of the argument let's just say that you need to boot a UEFI-less OS (and on bare metal, because of whatever reason).

Of course you need the services provided by CSM.

Now, there's this voice that Intel >2020 systems got it gutted for good (depends on who you ask) but I could tell you my 2021 Comet Lake AN515-55 could still be made to reason with it.

And I just checked one old bios version for your laptop and I found drivers named "BiosVideoDxe", "LegacyBiosDxe" and "LegacyBiosPlatformHookDxe", so I would expect the thing still to work if you just could toggle the setting (there are also examples from other vendors of Renoir still supporting legacy boot).

If you are extremely lucky, you already mentioned having disabled secure boot.. you can just try to disable fast boot, modern standby, or any SATA mode that isn't AHCI (remember the option only comes out with the CTRL + S combo). And then perhaps it will become selectable.

Otherwise, I'm afraid it becomes an increasingly harder game of taking guesses. Maybe you can get some of the advanced menu codes to work, and everything unlocks by itself. Possibly you can play with your UEFI variables (the Boot Mode value is set inside the SystemConfig store, which should correspond to the Setup namespace with guid A04A27F4-DF00-4D42-B552-39511302113D).

Or last but not least you can mod your bios. But it's probably gonna be write protected, and on AMD systems there are apparently no workarounds. So you are gonna need a hardware flasher, on top of the usual mess that it already would entail.

It's been 4 months and I don't remember exactly all details but i remember that I couldn't change anything in the bios excapt the secure boot mode (on or off). After a tons of research I found a soulution that should have worked: link but it didn't... Like I said , can't remember what exactly didn't work but the UEFISEVEN (Mod or whatever) solution should have worked... — Caro, Aug 14 '21 at 20:08
There is a support thread here for the thing, maybe ask there (or well, one of the other bunch of forums specializing on the matter). The verbose and force_fakevesa options seem enticing for starters. If people could get even XP to somehow boot with uefi, no way you shouldn't. This said, my answer was pursuing a completely different path. — mirh, Aug 18 '21 at 15:40

Unable to change from UEFI to Legacy Mode

2 Answers2