Windows 10: System partition is MBR, so no access to UEFI. Any way to bypass that?

Hi,

My system partition is set to MBR, so access to UEFI from advanced startup options is missing.
I accidentally set the boot order to external HDD first, so whenever something is connected and I restart the computer, it tries to boot from the external device.

I can't convert the disk to gpt without formatting it, and the system is there so that's problematic.

Is there any way to do it anyway?
I thought EasyBCD BIOS Extender could do the job (it can't).
Maybe boot from an external device?

Thanks.

:)

 

FAT_FILE_SYSTEM when booting in to a USB

I have tried to export it using a MBR partition for BIOS or UEFI-CSM, MBR partition for UEFI and GPT partition for UEFI using a 4GB flash drive, and none of the attempts worked. I made sure that the file system was set to FAT32. I left the cluster size
as the default.

 

Triple Boot Windows 10, 7 and Ubuntu

I installed Windows 10 on a computer already having Debian Linux (testing) installed. It deleted my encrypted Debian partitions, but the problem may have been that the partition order was not sequential. It is also possible that this can only happen on MBR
partitions, I don’t know. I’ve never seen mis-ordered GPT partitions, but plenty of mis-ordered MBR partitions.

I also installed Windows 10 on another MBR partitioned computer and I didn’t compromise my existing Debian Linux installation.

Background information:

• MBR stands for Master Boot Record.
• GPT stands for GUID Partition Table.
• MBR and GPT is the partition table used to define partitions on a storage device such as a hard disk drive or an SSD.
• MBR is widely used on BIOS based computers. BIOS stands for Basic Input/Output System and it is the main firmware of a PC.
• GPT is used with (U)EFI based computer. UEFI (formally EFI) stands for (Unified) Extensible Firmware Interface and it is the successor of the BIOS as the main firmware of a computer.
• Some early UEFIs feature a Compatiblity Support Module, which emulates a BIOS.

If your computer has UEFI then you will be using a GUID partition table, when your computer has a BIOS or if you use the CSM (Compatiblity Support Module) of the UEFI, then your computer will use the MBR partition table.

I made the observation that when installing on a GPT partitioned UEFI system, multi-boot is much easier, BUT some UEFI implementations don’t manage the boot device list correctly and you would have to manage that list manually. The easy way is to use GRUB
as the fallback EFI boot loader, and configure the GRUB boot menu so that you can boot all your EFI-compatible operating systems (and with some tricks, like Hybrid-MBR, also some BIOS-only non-EFI-compatible operating systems)…

It is also noteworthy that all your operating systems would have to fully support secure boot if you want it – which means, if only one operating system (of function, such as a UEFI boot loader like GRUB) cannot handle secure boot you would also have to
disable secure boot for all operating systems. Or you are really a hardcore user and like to enable/disable it all the time in the UEFI setup (which takes time and costs nerves) – be warned, you could get insane!

It is also noteworthy that if Windows was installed with secure boot enabled, it will have to be reinstalled without secure boot, otherwise it will not work. (The reverse is also true.)

So, I would think: GPT shouldn’t be too much of a problem, MBR might be. But both can be quite an adventure!

But whatever you do: a backup would be wise.

 

Why not click on restart from the power icon and when the computer reboots then press the key for entering bios setup?

 

That's impossible with W10

 

That is not true. You must, however, perform a restart to get to the BIOS, rather than from shutdown if you have Fast startup enabled.

 

OP's Prior MBR / UEFI thread
https://www.tenforums.com/installatio...gpt-issue.html

last reported with how he solved the issue...

 

If I'm correct, the BIOS resides in the motherboard right? So if I could access it with some external boot media, that would solve the problem. Wouldn't it? or maybe the external media has to be GPT, in which case that's impossible.

 

The bios/UEFI does reside on the motherboard. And that is the exact reason that the standard way of accessing the bios/UEFI is to press the designated key during the initial boot screen after a restart. On some computers it's ESC, Del, F1, F2.

You might think it is impossible with Windows 10, but from a restart (not shutdown with fast startup enabled) that is the standard way to do it. The manual for your motherboard or pre-made computer will tell you what key you need to press.

 

Is that your Final Answer ?

*Roflmao2

You are Correct....

 

BIOS can be accessed even without any drives let alone OS.
What is BIOS (basic input/output system)? - Definition from WhatIs.com

 

Hi CountMike,

How can I do it in my current situation?

 

User manual: https://download.lenovo.com/consumer...Info:UserGuide

According to it:




Is how to enter BIOS.