[SOLVED] Unable to Boot from UEFI ?

Dec 14, 2021
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Hi Gang

Dell Precision 3620 with i7-7700K, running Windows 10.

Unfortunate power outage during 'surprise' Bios Flash to version 2.21.0 - was not aware of auto 'update feature' in bios settings. In any event, the error seemed to fix itself when machine rebooted and the flash appeared to continue to completion. When formatting new SSD system drive with Microsoft W10 Pro Full Install Disc, was unable to boot off the Optical Drive (and the disc), without FIRST changing from UEFI to Legacy in 'Boot List Option'.

Completed OS installation successfully. However when attempting to reset Bios to 'default settings' (Booting in UEFI), cannot boot until once again changing back over to Legacy Boot. It should be noted that the system runs fine booting in Legacy Mode. Dell Diagnostics run successfully several times with no errors. RAM is new and compatible. Booting from/into UEFI worked fine before Flash revision.... Current Disk Partition ... Legacy Only ???

Any options or conclusions?

Thanks for all your suggestions ... :confused_old:
Mike
 
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Dec 14, 2021
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Hello again Ivt :)

Not sure about MBR? Master Boot Record?

In any event, you mentioned: "On most systems the MBR only works with Legacy mode"

Am I to understand once the Bios was updated to version 2.21.0, there's a possibility the system lost the ability to boot in
UEFI? Or is it just being stubborn?

As I understand it, the earlier Legacy type Bios was changed (modernized) to UEFI before the manufacture of this machine (2017)? Just wanted to rule out 'other' possible damage/harm when the flash was interrupted. I don't believe so since the flash was completed. Trust me I had no idea this was an 'AUTO' option in the Bios or I would have surely UNCHECKED that box.

Thank you
 
Hello again Ivt :)

Not sure about MBR? Master Boot Record?

In any event, you mentioned: "On most systems the MBR only works with Legacy mode"

Am I to understand once the Bios was updated to version 2.21.0, there's a possibility the system lost the ability to boot in
UEFI? Or is it just being stubborn?

As I understand it, the earlier Legacy type Bios was changed (modernized) to UEFI before the manufacture of this machine (2017)? Just wanted to rule out 'other' possible damage/harm when the flash was interrupted. I don't believe so since the flash was completed. Trust me I had no idea this was an 'AUTO' option in the Bios or I would have surely UNCHECKED that box.

Thank you
I can't tell what happened with your Bios after the unsuccessful flashing, but this article explains very well why you may have problem with using MBR disk on an UEFI system.

https://www.diskpart.com/gpt-mbr/can-i-use-mbr-with-uefi-0825.html
 
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When formatting new SSD system drive with Microsoft W10 Pro Full Install Disc, was unable to boot off the Optical Drive (and the disc), without FIRST changing from UEFI to Legacy in 'Boot List Option'.
Completed OS installation successfully.
However when attempting to reset Bios to 'default settings' (Booting in UEFI), cannot boot until once again changing back over to Legacy Boot.
If windows is installed in legacy mode, then system can boot in legacy mode only.
To switch to UEFI mode, you'd have to either
reinstall windows in UEFI mode or
use MBR2GPT utility to convert windows installation to UEFI.

Try to change your boot disk frm MBR to GPT to see if the computer can boot in UEFI mode.
And no, you can't just convert disk partitioning from MBR to GPT and expect it to boot.
This must be done properly with appropriate tools.
 
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Dec 14, 2021
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Thanx for the explanation. I wasn't aware of this issue. In fact, (unless I'm missing something), I don't believe I had this problem with a new HDD style drive as I was trying to format a new SSD drive? Does it matter? Or does the issue exist regardless of the style drive? Perhaps the newer Bios is what changed the situation making it necessary to convert the partitions to GPT BEFORE format? Just to re-clarify I definitely have Bios version 2.21.0 - I don't understand how/why Dell manufactured the Precision 3620 i7 7700K in 2017 'WITH' UEFI capabilIty when one cannot format a new system drive using UEFI and instead forced to format using Legacy? Sorry ... I'm missing an explanation ...

Thanks again ...
 
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I wasn't aware of this issue.
There is no issue.
If you install in legacy mode, system gets installed in legacy mode.
If you install in UEFI mode, system gets installed in UEFI mode.
You choose install mode yourself by booting into appropriate mode.

See here boot menu for booting from USB flash drive:
USB Disk choice boots into legacy mode.
UEFI USB Disk boot choice boots into UEFI mode.

 
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Dec 14, 2021
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Hello SkyNetRising

Thanks Again! :)

My understanding is that UEFI is modernized and more desirable than Legacy, (it does have some benefits) But I wasn't aware of the needed conversion from MBR to GPT before a format could be accomplished. In fact I finally got a prompt during pre-format which clearly indicates conversion is necessary:

Prompt-1
Prompt-2

And BTW does this apply to both SSD and HDD Drives? The only problem now is that I've already DELETED/Erased the new SSD system drive. SkyNet's JPG link seems to be a broken? It might be better to take the drive out and place it in a Dock and perform the conversion with my other desktop? But the other system is running on W7?

And BTW I do believe this all came about after the unexpected Bios flash into 2.21.0 (as I didn't have this problem prior). :(

Thank You Again Ivt & SkyNet! :rolleyes:
(appreciate it)
 
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In fact I finally got a prompt during pre-format which clearly indicates conversion is necessary:
Prompt-1
Prompt-2
Have only single drive connected, while installing windows.
Clean the drive before installing windows onto it (delete every existing partition on it).
Windows install process will partition and format drive as necessary.

If your drive is already partitioned in MBR and has existing partitions on it, then windows install can't automatically convert drive to GPT partitioning.
The drive must be empty.
 
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Dec 14, 2021
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Hi SkyNet

Nice to see you again ...

I'll try again but I assure you I already tried numerous times with nothing else connected to the motherboard (all other devices and drives gone) and yet I still couldn't get a format in UEFI

But we'll see ....

And thank you ... (y)
 
Dec 14, 2021
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Have only single drive connected, while installing windows.
Have tried that - but will try again .. :)

Clean the drive before installing windows onto it (delete every existing partition on it).
If you're talking about making corrections (deleting those partitions using existing format tools during the format), we'll see .. :confused_old:

Windows install process will partition and format drive as necessary.
Hope so ...:cautious:

If your drive is already partitioned in MBR and has existing partitions on it, then windows install can't automatically convert drive to GPT partitioning.
The drive must be empty.

I asked if this was best accomplished by taking the new drive out and placing it in a dock?
 
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Dec 14, 2021
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Thanks SkyNet :)

'Will Do' .... Here we go again .... 🆒

Although I've been formatting for sometime, the issue of having to convert from MBR to GPT was something I hadn't come across before ... This may be oversimplifying it but with all the explanations and research online there wasn't a hint of:

"Just trust the ordinary format process but get rid of all other partitions first and you'll be fine "

Be back soon .... (y)
 
Dec 14, 2021
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I can't believe how easy that was !!! :D

Thanks again SkyNet & Ivt!

"Windows install process will partition and format drive as necessary"


As I mentioned: don't let the excessive technical jardon throw you ... "Just trust the ordinary format process but get rid of all other partitions first and you'll be fine "

Wish I could leave a TROPHY for both you guys!

Thanks Again!
 
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