boot drive detection Evos SSD) by my BIOS

Hi,
In recent months I have encountered a windows boot failure. The only way to get my system running was by repeated power cyycling.Up to 4 or 5 times to get a bios post and boot.
I suspected the the power good signal was being delayed. However, testing of my then PSU (Corsair 650) showed a 12v rail instability, so I decided to buy a new one.
The problem has now presented slightly differently. The first power on is OK (by OK I mean case fans on, CPU cooler active etc) but I don't seem to be getting any indication that POST is active or has completed. I look for a quick flash on of my monitor status lights to show this.
I power down and turn on again quickly (within a few seconds of the power down) and I then get the indication that POST has commenced. The system doesn't boot though and I get a UEFI screen saying that "ATA/ATAPI devices detected", followed by a line saying "the system failed to boot several times and either press F2 and change my configuration, or UEFI will continue to boot the system in 5 seconds"
I let the the timer count down, and then my system boots normally.
My boot drive is a samsung 850 EVO and all drives (internal and external are GPT. I have also switched windows from legacy to UEFI boot mode.
The UEFI message seems indicate a slow detection of my Samsung drive.Any help on this matter would be gratefully received.
regards
Dave
PS my version of Windows is 10 pro - version 21H2 (os build 19044.1266)
D

Hi there.
My line of investigation was started by a failure of my system to (seemingly) post (no BIOS splash, and no Windows boot.
Initial repeated pwer cycling to get it to boot led me to look at my PSU. I thought it was a late "Power-good" signal.
At this point my bios was legacy, as was Windows. and my drives were MBR.
I then looked at my EVO, but that was fruitless as all seemed perfectly OK. Although I did replace the SATA data cable as a precaution.
I then returned to my BIOS, checking that all my SATA devices were present, and then to the Boot set up page.
It was there I noticed that the BIOS was in Legendary mode and investigated this using the forums tutorial.
The conversion to GPT was done following those instructions. I could get a boot by repeated power cycling, but then decided to replace the PSU - the 12V rail was testing low.
That was the next thing done.
The new PSU has improved improved things in as much as I now only needed 2 power cycles to get a POST, and the stalling of the boot loader by the BIOS - saying there was a load failure (as described in my initial post..
The only boot options I get in the BIOS are "Windows Boot Manager" or "UEFI shell", no individual SATA devices being shown now,
Boot #1 is set to WBM.
I now longer get the BIOS error screen with the timedown. This seems to have resolved itself., after rechecking drive connections of all my SATA devices
I am now left with a failure to boot on first power up, but always on the second.
I can't quite see why I need WBM as I don't have a multi boot system - Just Win 10.But it seems to be a component of the GPT based system. I am also not sure how this architecture will let boot from another device e.g flash drive, or my DVD.
I use a Ventoy USB to load up various utilities for diagnostics, Acronis disk recovery,WinRE ? but don't know whether plugging it in and restarting will work now.
Thanks for your time though

dch1950 said:

Hi there.
My line of investigation was started by a failure of my system to (seemingly) post (no BIOS splash, and no Windows boot.
Initial repeated pwer cycling to get it to boot led me to look at my PSU. I thought it was a late "Power-good" signal.
At this point my bios was legacy, as was Windows. and my drives were MBR.
I then looked at my EVO, but that was fruitless as all seemed perfectly OK. Although I did replace the SATA data cable as a precaution.
I then returned to my BIOS, checking that all my SATA devices were present, and then to the Boot set up page.
It was there I noticed that the BIOS was in Legendary mode and investigated this using the forums tutorial.
The conversion to GPT was done following those instructions. I could get a boot by repeated power cycling, but then decided to replace the PSU - the 12V rail was testing low.
That was the next thing done.
The new PSU has improved improved things in as much as I now only needed 2 power cycles to get a POST, and the stalling of the boot loader by the BIOS - saying there was a load failure (as described in my initial post..
The only boot options I get in the BIOS are "Windows Boot Manager" or "UEFI shell", no individual SATA devices being shown now,
Boot #1 is set to WBM.
I now longer get the BIOS error screen with the timedown. This seems to have resolved itself., after rechecking drive connections of all my SATA devices
I am now left with a failure to boot on first power up, but always on the second.
I can't quite see why I need WBM as I don't have a multi boot system - Just Win 10.But it seems to be a component of the GPT based system. I am also not sure how this architecture will let boot from another device e.g flash drive, or my DVD.
I use a Ventoy USB to load up various utilities for diagnostics, Acronis disk recovery,WinRE ? but don't know whether plugging it in and restarting will work now.
Thanks for your time though

have you checked for an updated bios?

tomdsr said:

have you checked for an updated bios?

Yes and my mobo has been on P1.4 for a while now. Nothing newer is available
Dave.

Hmmm, the matter of the 12V rail is interesting, and while it was low (tested with a plug in PSU tester) , but it must have eventually provided the "power good" signal after repeated power cycles.
Equally, windows load and boot seems to be fine once it actually starts.Thus we have a situation where the first power up doesn't initiate POST and hence to windows load., but a power off and on again always produces a successful boot of Windows.
Puzzling :)

Well, I think I have managed to fix this problem. Although why the solution worked I am not sure about.
I spent yesterday morning checking all mobo connections. During this I discovered that my front panel RESET button was not connected correctly (probably irrelevant) and I decided to to reorder my SATA data cables, putting my EVO (Boot drive) on pole position i.e. SATA_1. This has resolved the problem My machine now powers up normally and boots to Windows.
I must proffer my thanks for your kind assistance and admit that I gained avaluable insight into to the UEFI and Windows Boot Manager. along the way.
regards
Dave H (Junior Member)
PS what's a rep point?
D.