Question CSM Support disabling bricked my pc

Aug 29, 2022
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Hello! Yesterday I had such an unlucky situation. Tried to enable SecureBoot and TPM on my Gigabyte B450M S2H MOBO. I read that to enable this option I was supposed to disable CSM Support. I did it and then went to PK option and pressed "UPDATE". After that I saved and exit BIOS and it all began. My computer was not working, there was no signal at my monitors. I thought "okay maybe it is just an error" and reset the computer. Still no signal on monitors, my mouse and keyboard did not light up like the USB's doesn't work. Tried to pull out and in CMOS battery, connect CLR_CMOS pins with screwdriver, try to boot without my HDD and SSD drive and it still doesn't work. Technicaly hardware works correctly, CPU, GPU and case FANS works fine but nothing appears on my monitors. No UEFI, no Windows. It is completely dark, nothing shows up. I am totally stucked, I can't do anything with it. Please help me as soon as you can!

My PC Specs:
MOBO: Gygabyte B450M S2H
CPU: R3 3100
RAM: G.SKILL AEGIS 3200MHZ 16GB
GPU: SAPPHIRE RX570 8GB
SSD: CRUCIAL 240GB
PSU: SPC VERO L3 500W
 
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Aug 29, 2022
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then to reset cmos, you have to turn off PSU, there shouldb e off switch on it
then press power button on PC case to discharge any residual power
then short clear_cmos pins for few seconds
then turn psu on and power up pc, might take few minutes and few reboots before it boots up
I left it for 20 minutes after reseting CMOS and stil nothing, do u have any other possible solutions?
 
Sep 7, 2022
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Literally the exact same issue i'm having. I read somewhere that If you have integrated graphics on your CPU then plug your HDMI into your motherboard the display will work again. But I don't and I would assume neither do you. Been a week for me without a working pc. Lmk if u figure it out

Edit:
Did some more searching and found this thread
https://forums.tomshardware.com/thr...ng-after-disabling-csm.3711404/#post-22372257
 
Last edited:
Aug 29, 2022
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Literally the exact same issue i'm having. I read somewhere that If you have integrated graphics on your CPU then plug your HDMI into your motherboard the display will work again. But I don't and I would assume neither do you. Been a week for me without a working pc. Lmk if u figure it out

Edit:
Did some more searching and found this thread
https://forums.tomshardware.com/thr...ng-after-disabling-csm.3711404/#post-22372257

Unfortunately I couldn't do anything with this. Left my PC in PC service and they couldn't do nothing xd. I gave up and bought new mobo yesterday. Now it works completely fine.
 

Colif

Win 11 Master
Moderator
did you do it this way?


were drives formatted as MBR or GPT?

black screen after enabling Secure boot normally means drives were formatted as MBR.
disabling CSM and turning on Secure boot... there is a step missing in all the instructions online. You need to convert drives from MBR to GPT before swapping the BIOS or windows won't boot.

you "fixed" it the expensive way. But oh well, it works now :)
 
Aug 29, 2022
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did you do it this way?


were drives formatted as MBR or GPT?

black screen after enabling Secure boot normally means drives were formatted as MBR.
disabling CSM and turning on Secure boot... there is a step missing in all the instructions online. You need to convert drives from MBR to GPT before swapping the BIOS or windows won't boot.

you "fixed" it the expensive way. But oh well, it works now :)

Yea i had to do it that way, i couldn't even enter to the bios to Change mbr to gpt so after week in Pc service i gave up and bought mobo. I was hoping about fixing it but it doesnt work :/
 

Colif

Win 11 Master
Moderator
Its a trap for some boards as there is no way to flash their bios without seeing the display.
resetting the CMOS may have helped.

Older Gigabyte boards have dual bios, meaning you can force PC to flash a backup copy of a bios with default settings onto normal one at startup
Newer ones have Q Flash Plus which lets you reflash the bios with nothing other than a power supply attached to Motherboard.
Alas, your board was inbetween and doesn't have either feature. Not really nice if you ask me.
 
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Sep 7, 2022
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Sep 10, 2022
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So the only way to fix this if you have a motherboard like mine with no dual bios or any other bios recovery feature, your only cheep option it s to buy a dedicated tool for flashing the bios by attaching the clamp from the device directly to the motherboard's bios chip. I have the same problem and now I am on my way to grab 1 of those devices witch can be as cheep as 10 $.USB CH341a will be the model il be useing, but this is just the device itself you will also need the clamp I was tallking about so be sure to buy 1 that includes both