Missing Bootable devices in BIOS after removing Ubuntu dual boot

Windows 10 Pro, Version 2004, OB build 19041.572

I have a Gigabyte GA-Z77X-UP4 TH mb. My BIOS has been set to UEFI for a while now and I had no issues with it. When I needed to boot into some live cd or flash drive, I would press F12 at boot and have a list of bootable devices to choose from. I also saw all of these devices in the BIOS, where I could choose them for a boot order.

I found myself using Ubuntu quite often with the “try ubuntu” option, so last week I decided to install it as a dual boot. I used a secondary hard drive for the Ubuntu partitions (not C.) After a few days, I decided to get rid of the dual boot. I went through all the steps to delete it; deleting the ubuntu partitions, and using diskpart to get GRUB removed from the boot loader. Although after this, the computer would boot right into Windows, for some reason, the ubuntu was still listed in bcdedit /enum firmware, so I also used bcdedit /delete to delete that.

Here’s the issue that I have now:

When I press F12 to boot into a live CD (or flash drive), the only boot option is Windows. In my BIOS, in the boot order section, I can only choose Windows; there is no more list of all my drives and CD ROM to choose to boot from.

The only way to get back the list of bootable devices is if I switch the “Boot Mode Selection” from “UFEI only” to anything else, like “UEFI and LEGACY” or “LEGACY only.”

However, if I switch to anything other than “UEFI only,” the computer won’t boot into windows; I get an error saying, “Reboot and select proper boot device.”

I am 99% sure that before I did the dual boot, I had “UEFI and LEGACY” selected in the BIOS and in Windows System information, it would show that my BIOS is UEFI.

What I need now is to be able to see a list of bootable devices in my BIOS, including my CD ROM, so that I can choose to boot from a CD or flash drive when desired, and of course, that my computer should boot into Windows when I just want to boot normally.

Notes:

1. Fast boot is disabled.
2. I read that Secure boot should be disabled but I don’t have that setting.
3. I read that CSM should be disabled but I don’t have that setting.
4. My C drive (SSD) is GPT, Active & System.

Any suggestions?

Have you read the manual: https://download.gigabyte.com/FileLi...x-up4_th_e.pdf?
Your problem does not exist on my GIGABYTE GA-H81M-DS2.

Matthew Wai said:

Have you read the manual: https://download.gigabyte.com/FileLi...x-up4_th_e.pdf?
Your problem does not exist on my GIGABYTE GA-H81M-DS2.

Yes, I looked at the manual and it doesn't have the words "secure boot" or CSM. It also says that we can choose a device to boot from. I already know that and that's where I have my issue.

I'm not sure what you mean by my problem doesn't "exist" by you. It should NOT exist by you, otherwise you'd have a problem too. I'm asking if someone knows a solution to the problem so that we BOTH don't have it! :)

Do you mind telling me if your BIOS is shown as UEFI in Windows or not?
If yes, can you please tell me what BIOS settings you have in the "OS type" fields show in the screenshot below?



- - - Updated - - -

There is an article about my board here that shows a screenshot of HIS BIOS and he DOES have the CSM options. I don't. I'm not sure that's the solution to my issue but it's a start. Maybe I should flash my BIOS to vf9 or vf10b (I've used both in the past without issue)

Here is HIS screenshot:

My Windows uses UEFI as shown below:



The following shows my boot mode:





The following shows my boot devices:

zvit said:

I read that CSM should be disabled but I don’t have that setting

My manual says the following:

CSM Support
Enables or disables UEFI CSM (Compatibility Support Module) to support a legacy PC boot process.
Always Enables UEFI CSM. (Default)

In post #3, change storage boot option control to UEFI and Legacy.

NavyLCDR said:

In post #3, change storage boot option control to UEFI and Legacy.

At my end, "UEFI and Legacy" does not exist under "Storage Boot Option Control".

Storage Boot Option Control
Allows you to select whether to enable the UEFI or legacy option ROM for the storage device controller.
Disabled: Disables option ROM.
Legacy: only Enables legacy option ROM only. (Default)
UEFI: only Enables UEFI option ROM only.
Legacy First: Enables legacy option ROM first.
UEFI First: Enables UEFI option ROM first.
This item is configurable only when CSM Support is set to Always.

Matthew Wai said:

This item is configurable only when CSM Support is set to Always.

And @zvit stated in post #3 that his motherboard BIOS does not offer "CSM Support". Nor does "CSM" appear in his motherboard manual. I suspect the @zvit might be running an outdated BIOS version as he also hinted to in post #3.

Thank you all for your help. I fixed it.

First, @NavyLCDR I didn't say that my motherboard didn't support CSM, I said that I don't see that option in my BIOS although I showed a screenshot from someone else with my same board that had it.

What I did was first flash my BIOS back to version f9 (it was on F10b - yes, I know it's a "beta" but it's been "b" for 10 years and I never had an issue with it) and that gave me back the CSM support. CSM Support must be set to Always or else you will get a loop that will keep booting back into the BIOS (or worse, you will get one long beep and two short ones and think you have a problem with your video card (if you Googled that beep sequence) or your RAM, which actually you don't!

But I still didn't have "Windows Boot Manager" in my bootable devices.

So I decided that my EFI partition must be messed up. I booted into a live CD (I have many but for this I used "WinPE 10 Sergei Strelec 2019.10.02" which has a few BCD fix tools. It fixed the BCD and EFI for me.

That's it. Now I can select all bootable devices, I have "Windows Boot Manager" which works fine.

There is just one more non-critical issue that I need to solve.

The way I used to work is have my BD DRIVE be the first bootable option in case I need to boot from a live cd. The way it's supposed to work is, BIOS should first try to boot from Option 1 (the bd drive) and if there is no inserted disk, it would go to option 2 (Windows Boot Manager) and Windows would boot. Yes, this adds a few seconds to the boot time but I don't care.
The problem is that now, when I select the BD Drive to be boot option 1, I get an error that no operating system was found. This shouldn't be happening; it should be booting from option 2 (Windows) when no CD is inserted.

I have long been using the following settings, which work fine.

Select "Windows Boot Manager" as option 1. If need be, insert a bootable USB device and select it on the (F12) boot menu.
If I don't touch the boot menu, my PC will always boot into installed Windows whether I have inserted the USB device or not.
My PC will be booted from the USB device only if I have selected it on the boot menu.
I never pay attention to option 2.

zvit said:

I didn't say that my motherboard didn't support CSM, I said that I don't see that option in my BIOS

I don't see that option in my UEFI BIOS either, but CSM support is enabled by default.
I can boot into installed Windows in UEFI mode and boot into installed Linux in Legacy mode.