Bios failure after failed windows update

[Juantorolo]

Hi Community,

I recently acquired a Prodesk 400 G7 desktop. It came without HD so I installeda new nvme and, after reinstalling windows 11, an update started and due a power problem, system turned off while updating.

After recovering power PC did not boot after removing all peripherals and resetting CMOS, I get a beep/led code. 2 red/long beeps and 2 white/short beeps (BIOS corruption signal).

Looking around HP support page I came across a way to fix this, but it did not seems to work, I only get an black and white HP logo on screen while if booting with a USB thumbdrive connected or the beep code if no storage is attached.
Could you please help?

(Excuse my English, as I am not a native speaker)

[NonSequitur777]

@Juantorolo,

Welcome to our HP Community forum!

OK, the 2 long red beeps followed by 2 short white beeps indicate BIOS corruption, which is consistent with the system losing power during an update.

If the USB drive you are using is a Windows 11 installation USB, it will not repair a corrupted BIOS. The BIOS must be recovered before Windows can boot or be installed.

I would recommend doing the following:

1. Obtain the exact product number of your ProDesk 400 G7.
2. On another working Windows PC, download the latest BIOS SoftPaq for your specific model from HP.
3. Run the SoftPaq and use the option to create a BIOS Recovery USB flash drive.
4. Disconnect AC power from the ProDesk and remove the NVMe SSD.
5. Connect the BIOS Recovery USB to a rear USB port.
6. Hold the Windows + B keys, press the power button, and continue holding Windows + B for several seconds.
7. Wait several minutes to see if the HP BIOS Recovery screen appears.

A few questions:

• What is the full product number of the ProDesk 400 G7?
• Does the HP logo remain on the screen indefinitely, or does it eventually disappear?
• Have you already tried a BIOS Recovery USB created from the HP BIOS package, or only a Windows 11 installation USB?

If a properly prepared HP BIOS Recovery USB does not start the recovery process and the system continues to show the 2-red/2-white error code, the BIOS chip may need to be reprogrammed externally with a SPI programmer or the motherboard may need to be replaced.

Please be reminded that your PC is reporting the 2 red / 2 white BIOS corruption code, I would focus on recovering the BIOS first. A Windows 11 installation USB can reinstall Windows, but it cannot repair a corrupted BIOS. Once the BIOS is functioning normally and the beep code is gone, you can proceed with installing Windows if necessary.

Kind Regards,

NonSequitur777

[Juantorolo]

Thanks for answering!

- This is a hp prodesk 400 G7 MT with Product number 11M72EA#ABE

- HP logo stays indefinitely on screen.

- I did try HP BIOS Package after downloading it using serial number to locate the file, but in a front USB (is also directly on the motherboard) I just tried in  back USB, with the same results (none)

[Juantorolo]

Also, if I push escape or f10 I get  message about accessing boot or factory reset, etc. but those applications never appear on screen. Windows+B does nothing, only HP logo appears and stay there until PC is turned off.

[NonSequitur777]

@Juantorolo,

The fact that you can see text messages about accessing the boot menu or F10 Setup when you tap keys —but the screen permanently freezes right after— means your hardware is healthy, but the motherboard's main firmware is entirely hanging mid-way through its Power-On Self-Test (POST). It cannot hand execution over to the USB drive or built-in menus.

Let's force the motherboard to bypass this frozen state with a deeper hardware reset:

1. Perform a 15-Minute Hard RTC Reset: Unplug the power cord from the wall. Open the case and remove the round, silver coin-cell CMOS battery from the motherboard. Press and hold the computer's power button down continuously for 60 full seconds to completely drain the board's capacitors. Leave it sitting completely disassembled for 15 minutes before reinstalling the battery and plugging it back in.
2. Isolate the RAM and Hardware: Make sure your NVMe SSD remains completely removed. Additionally, pull out all RAM sticks except for one single stick in the primary slot. If the freeze continues, swap it for your other memory module to ensure a corrupted memory map isn't blocking the POST routine.
3. Change the USB Port and Key Layout: Make sure your recovery USB drive is 32GB or smaller and explicitly formatted to FAT32 (large or exFAT/NTFS drives fail here). Plug it exclusively into a black USB 2.0 port on the back of the PC, not the front ports.
4. Use the Alternate Command: Turn the PC off. Press and hold Windows + V (instead of B). Press the power button for 2 seconds, let go of the power button, but keep holding Windows + V down until the screen flashes or changes.

If you give these a shot, let me know:

• Does the deep 15-minute battery pull change the screen behavior or the beep codes when you turn it back on?
• What is the storage size of the USB flash drive you are currently using for the recovery pack?

Kind Regards,

NonSequitur777

[Juantorolo]

Again, many thanks for taking time responding. Unfortunately I am out for the weekend. I will test what you suggested and let you know the results.

[Juantorolo]

Hi NonSequitur777,

I did try what you asked me to do, but the problem is still on. Also tried to change the keyboard to the  USB port with the keyboard pictogram in the back of the PC, just next to the USB thumbdrive.

I only have a single RAM module, but I did try exchanging RAM sockets (I will try to find another module today) and alsow ill try with another smaller thumbdrive.

About your questions:

• Does the deep 15-minute battery pull change the screen behavior or the beep codes when you turn it back on? =>  Just the same B/W screen with HP logo, but beeps only occurs if no storage is attached.
• What is the storage size of the USB flash drive you are currently using for the recovery pack? =>32Gb formatted in FAT32 
  

I am starting to think it could be a physical error in BIOS chip.

Anyway, thanks for the effort.

[NonSequitur777]

@Juantorolo,

Since the system still hangs indefinitely at the HP logo after all recovery attempts, and the BIOS Recovery USB is not being executed, I agree that a firmware-level failure is increasingly becoming the most probable explanation.

The fact that the HP logo appears suggests the boot block portion of the BIOS is still intact, but the main BIOS image may be corrupted beyond what the built-in recovery mechanism can repair.

Before condemning the motherboard completely, I would still try:

• A different USB flash drive (preferably 8 GB or 16 GB, FAT32 formatted).
• A different memory module if available.
• Recreating the BIOS Recovery USB from scratch using the latest BIOS package for product number 11M72EA#ABE.

If those tests produce exactly the same result, the remaining repair options are generally:

1. Reprogram the SPI BIOS chip externally using a programmer such as a CH341A and a known-good BIOS image.
2. Replace the motherboard.

Because the ProDesk 400 G7 MT uses a socketed CPU and otherwise appears functional, an external BIOS reflash is often worth attempting before replacing the board, especially if you have access to SPI programming equipment or a repair shop that performs firmware recovery.

If you can post the motherboard's SSID number (usually a four-character code printed on a sticker on the motherboard) or you can find it in System Information, looking to the right of "BaseBoard Product" and a photo of the BIOS chip, forum members may be able to determine whether the chip can be reprogrammed in-circuit or requires removal from the board.

Kind Regards,

NonSequitur777

[Juantorolo]

Hi NonSequitur777,

I did try everything you suggested and everything in my bag of tricks, but still no bios Update. There is no repair centre for computers in my country, as all had been asphyxiated by big shops around them. I have last resort and I will try a friend of my who works in something similar

If not possible to fix it in any way, I will use the remaining hardware in another build, as the MB seems to be unrecoverable.

My most sincere thanks for your help.

[NonSequitur777]

@Juantorolo,

You are most welcome -this was a very valiant effort indeed!

Best wishes,

NonSequitur777