Question Assistance Needed: Gigabyte B450M H Secure Boot Update Caused System Reboot Loop

[essqsq]

I'm facing an issue with my Gigabyte B450M H motherboard. After enabling Secure Boot and accidentally updating the Platform Key (PK) in the BIOS without having a USB stick with the PK file, I didn't have a USB stick with that PK file or anything—I simply clicked 'Update,' and the system prompted me to reboot without saving changes. Now, my system is stuck in a reboot loop, and I can't access the BIOS or boot into Windows. Additionally, the back panel USB ports, Ethernet port, and other components are not receiving power and remain inactive. The screen stays black.

Here are the details of my system:

- CPU: Ryzen 5 3600
- GPU: DUAL RTX2060 6G EVO
- OS: Windows 11 23H2
- SSD: Kingston SSDNow 2.5" SATA III A400 Series 480GB
- RAM: Kingstom ValueRAM KVR26N19S8/8 2x8GB 2666MHz
- MOTHERBOARD: Gigabyte B450M H rev.1.1

I updated the BIOS to [F64] from the Gigabyte website, enabled Secure Boot in custom mode, and encountered this issue after the accidental 'Update PK' action.

I've tried the following troubleshooting steps without success:

- Restarting the computer and pressing the Del key to enter the BIOS.
- Clearing the CMOS by removing the motherboard battery for a few minutes.

Everything was fine before the Secure Boot update. Can someone please help and guide me on how to fix this problem?

 

[elderMat7]

You can attempt this.

Try putting only ONE stick of memory, and it probably doesn't matter which one you use, in the A2 slot and then do the following. Do not skip ANY steps, even if you think they are not necessary or that you "know better". Also, make sure your display cable is plugged into one of the outputs on the graphics card and not the motherboard since that CPU has no integrated graphics.

BIOS Hard Reset procedure

Power off the unit, switch the PSU off and unplug the PSU cord from either the wall or the power supply.

Remove the motherboard CMOS battery for about three to five minutes. In some cases it may be necessary to remove the graphics card to access the CMOS battery.

During that five minutes while the CMOS battery is out of the motherboard, press the power button on the case, continuously, for 15-30 seconds, in order to deplete any residual charge that might be present in the CMOS circuit. After the five minutes is up, reinstall the CMOS battery making sure to insert it with the correct side up just as it came out.

If you had to remove the graphics card you can now reinstall it, but remember to reconnect your power cables if there were any attached to it as well as your display cable.

Now, plug the power supply cable back in, switch the PSU back on and power up the system. It should display the POST screen and the options to enter CMOS/BIOS setup. Enter the bios setup program and reconfigure the boot settings for either the Windows boot manager or for legacy systems, the drive your OS is installed on if necessary.

Save settings and exit. If the system will POST and boot then you can move forward from there including going back into the bios and configuring any other custom settings you may need to configure such as Memory XMP, A-XMP or D.O.C.P profile settings, custom fan profile settings or other specific settings you may have previously had configured that were wiped out by resetting the CMOS.

In some cases it may be necessary when you go into the BIOS after a reset, to load the Optimal default or Default values and then save settings, to actually get the hardware tables to reset in the boot manager.

It is probably also worth mentioning that for anything that might require an attempt to DO a hard reset in the first place, IF the problem is related to a lack of video signal, it is a GOOD IDEA to try a different type of display as many systems will not work properly for some reason with displayport configurations. It is worth trying HDMI if you are having no display or lack of visual ability to enter the BIOS, or no signal messages.

Trying a different monitor as well, if possible, is also a good idea if there is a lack of display. It happens.

 

[essqsq]

You can attempt this.

Thank you for your response; I truly appreciate it.

I followed all the steps mentioned in the post, but unfortunately, it didn't resolve the issue.

I created a short video showcasing my PC's behavior. In the video, you'll observe that it continues to restart every 10 seconds. Initially, all fans operate normally, but after some time, both the CPU cooler fan and one of the GPU fans stop working, as if they're lacking power. Additionally, the back panel, housing USB, Ethernet, and other ports, doesn't receive power. The Ethernet port briefly blinks orange on each restart, and my keyboard and mouse remain without power. The problem persists despite these observations.

 

[COLGeek]

A friend of mine had a similar issue. The "fix" was to swap in a GPU with an integrated GPU (Ryzen 3400G) and then resetting the BIOS as desired. Any compatible AM4 CPU with integrated video, would suffice.

Part of the swap is to remove the dedicated GPU while making the changes.

 

[essqsq]

Thank you for your insightful response and assistance! I appreciate the suggestion of using a CPU with integrated graphics. Unfortunately, I don't have one at the moment. Is there any alternative method you would recommend for resetting the BIOS without an integrated GPU?

A friend of mine had a similar issue. The "fix" was to swap in a GPU with an integrated GPU (Ryzen 3400G) and then resetting the BIOS as desired. Any compatible AM4 CPU with integrated video, would suffice.

Part of the swap is to remove the dedicated GPU while making the changes.

 

[COLGeek]

Thank you for your insightful response and assistance! I appreciate the suggestion of using a CPU with integrated graphics. Unfortunately, I don't have one at the moment. Is there any alternative method you would recommend for resetting the BIOS without an integrated GPU?

While troubleshooting the motherboard, I suggest removing the storage devices to ensure you don't corrupt them.

I would also remove all but one stick of memory, as well.

There is an old technique that may allow you access to the BIOS, as soon as you power the system on, place your hand on the keyboard and hold multiple keys down and keep them down. The system will register as a keyboard error and may allow you to access the BIOS to "fix" the problem.

Another thing to try (similar to above) is to repeatedly press the F2/DEL key (whatever allows normal access to the BIOS) upon power up. Quick repeated pressing.

 

[essqsq]

While troubleshooting the motherboard, I suggest removing the storage devices to ensure you don't corrupt them.

I would also remove all but one stick of memory, as well.

There is an old technique that may allow you access to the BIOS, as soon as you power the system on, place your hand on the keyboard and hold multiple keys down and keep them down. The system will register as a keyboard error and may allow you to access the BIOS to "fix" the problem.

Another thing to try (similar to above) is to repeatedly press the F2/DEL key (whatever allows normal access to the BIOS) upon power up. Quick repeated pressing.

Thank you for the detailed troubleshooting steps! I'll make sure to remove storage devices and minimize memory sticks.

However, I don't believe pressing keys on the keyboard will be effective for me since my keyboard doesn't show any power connection to the PC.
Moreover, it might be challenging due to the repeated loop of the PC restarting itself, as demonstrated in the video.

Still, I appreciate your suggestions and will explore other possible solutions.

 

[COLGeek]

Find a PS2 keyboard and see if that allows access.

 

[essqsq]

Find a PS2 keyboard and see if that allows access.

I attempted troubleshooting with a PS2 keyboard as well, yet the issue persists. The display remains black, and the backpanel lacks a consistent power supply. Upon the initial power-up, the PC initiates successfully, but after approximately 10 seconds, it enters a repetitive loop reminiscent of pressing the restart button during the system's startup – exhibiting a behavior akin to restarting itself. During the first power-on phase, all fans, including the cooler and one GPU fan, operate seamlessly. However, as the system begins to cycle through restarts, the cooler and one GPU fan appear to lose power, akin to a gradual decrease in energy, similar to a battery-powered lamp dimming when the battery is low.

Additionally, it's worth noting that the restart loop behavior can be visually and audibly observed in the video I mentioned earlier. This video provides a firsthand look at the sequence of events, offering both a visual and auditory insight into the recurring restart loop.

Moreover, for the convenience of everyone assisting with troubleshooting, I'll be posting the same video mentioned above below this message. This should provide a clearer understanding of the situation by offering a visual representation of the observed restart loop.

 

[COLGeek]

Other than trying to recover the motherboard with a G-series CPU as discussed earlier, the only other option I can think of is to swap the motherboard itself.

I know those are not easy options.

Do you have access to any other AM4 CPUs? I wonder if swapping any CPU would force a different behavior.

 

[SkyNetRising]

I've tried the following troubleshooting steps without success:
- Clearing the CMOS by removing the motherboard battery for a few minutes.
Can someone please help and guide me on how to fix this problem?

Removing battery is not enough.
There's still residual charge in PSU capacitors.
You have to also disconnect pc from power and press power button to discharge PSU capacitors.

Or do BIOS reset as described in motherboard user manual - using onboard CLEAR_CMOS jumper.

 

[essqsq]

Other than trying to recover the motherboard with a G-series CPU as discussed earlier, the only other option I can think of is to swap the motherboard itself.

I know those are not easy options.

Do you have access to any other AM4 CPUs? I wonder if swapping any CPU would force a different behavior.

I appreciate your suggestions, and I'm grateful for your help.

Unfortunately, I don't have access to another motherboard or AM4 CPUs at the moment. However, I'll reach out to a friend to see if they might have the components needed.

Thank you for your assistance and help.

 

[COLGeek]

I appreciate your suggestions, and I'm grateful for your help.

Unfortunately, I don't have access to another motherboard or AM4 CPUs at the moment. However, I'll reach out to a friend to see if they might have the components needed.

Thank you for your assistance and help.

Keep us posted on your progress. Good luck.

 

[essqsq]

Removing battery is not enough.
There's still residual charge in PSU capacitors.
You have to also disconnect pc from power and press power button to discharge PSU capacitors.

Or do BIOS reset as described in motherboard user manual - using onboard CLEAR_CMOS jumper.

Well, I followed the instructions from the message I'll quote below, which a kind gentleman mentioned above and instructed me to try.

Try putting only ONE stick of memory, and it probably doesn't matter which one you use, in the A2 slot and then do the following. Do not skip ANY steps, even if you think they are not necessary or that you "know better". Also, make sure your display cable is plugged into one of the outputs on the graphics card and not the motherboard since that CPU has no integrated graphics.

BIOS Hard Reset procedure

Power off the unit, switch the PSU off and unplug the PSU cord from either the wall or the power supply.

Remove the motherboard CMOS battery for about three to five minutes. In some cases it may be necessary to remove the graphics card to access the CMOS battery.

During that five minutes while the CMOS battery is out of the motherboard, press the power button on the case, continuously, for 15-30 seconds, in order to deplete any residual charge that might be present in the CMOS circuit. After the five minutes is up, reinstall the CMOS battery making sure to insert it with the correct side up just as it came out.

If you had to remove the graphics card you can now reinstall it, but remember to reconnect your power cables if there were any attached to it as well as your display cable.

Now, plug the power supply cable back in, switch the PSU back on and power up the system. It should display the POST screen and the options to enter CMOS/BIOS setup. Enter the bios setup program and reconfigure the boot settings for either the Windows boot manager or for legacy systems, the drive your OS is installed on if necessary.

Save settings and exit. If the system will POST and boot then you can move forward from there including going back into the bios and configuring any other custom settings you may need to configure such as Memory XMP, A-XMP or D.O.C.P profile settings, custom fan profile settings or other specific settings you may have previously had configured that were wiped out by resetting the CMOS.

In some cases it may be necessary when you go into the BIOS after a reset, to load the Optimal default or Default values and then save settings, to actually get the hardware tables to reset in the boot manager.

It is probably also worth mentioning that for anything that might require an attempt to DO a hard reset in the first place, IF the problem is related to a lack of video signal, it is a GOOD IDEA to try a different type of display as many systems will not work properly for some reason with displayport configurations. It is worth trying HDMI if you are having no display or lack of visual ability to enter the BIOS, or no signal messages.

Trying a different monitor as well, if possible, is also a good idea if there is a lack of display. It happens.

The only thing I haven't tried is disconnecting all the cables connected to the motherboard and, after some time, putting them back in their places.

Thank you for your assistance and help.

 

[steveb1976]

take out all ram,, and unplug any ssd,, turn psu power switch off. and turn of at main plug,, short "clear cmos pins" (screwdriver or 2pin cap). and hold for 30 seconds .. install ram, then turn plug on and psu switch on.. power on and if should jump to bios (as you have no ssd attached).. this will reset bio to defaults so you will have redo your bios setting for xpm ,etc.. torun off attach ssd and you will be back to how you was before the issue