CMOS CHECKSUM INVALID

[OBIOHA1]

Please I have been using my laptop for up to 3 years now and I just changed the battery because it's gone bad (my laptop switches off around 60%).

Now immediately after changing the battery, I'm getting the "CMOS CHECKSUM INVALID" error message. I have browsed, it's said my laptop main battery also serves as the CMOS battery. The guy that repaired the battery for me said I need to flash the laptop.

For now, I use F10>boot options>legacy support... to boot my system.

The guy changed my keyboard (island style), screen open/close hinges and battery. So he practically dismantled my system. Even my Bluetooth is no longer available, though I plan to use external one.

My laptop: HP Notebook - 17-by0104ng

Check out the laptop here: https://support.hp.com/bg-en/document/c06057432

Please I need help now. Thank you.

[Hawks_Eye · Accepted solution]

Hi @OBIOHA1 

Welcome to the HP Support Community! We're here to help you get back up and running.

Thanks for laying out the situation so clearly. After a full hardware teardown and battery replacement, it’s understandable to see a “CMOS CHECKSUM INVALID” error—especially on a model like the HP 17-by0104ng, which doesn’t have a separate CMOS battery and instead relies on the main battery to retain BIOS settings.

Here’s a structured approach to help you recover stability:

1. Reset BIOS to Default Settings

This clears any corrupted configuration and reinitializes system values.

• Power on the laptop and press F10 repeatedly to enter BIOS Setup.
• Navigate to Exit > Load Setup Defaults (or similar wording).
• Confirm and Save Changes, then exit BIOS.

2. Update or Reflash the BIOS

If the checksum error persists, flashing the BIOS can help restore integrity.

• Visit the HP BIOS download page for your model
• Download the latest BIOS update utility.
• Use a second PC to run the installer and create a BIOS Recovery USB Drive.
• Insert the USB into your affected laptop.
• Press and hold Windows + B, then press the Power button for 2–3 seconds. Release the power button but keep holding Windows + B until the BIOS recovery screen appears.

If that key combo doesn’t work, try Windows + V instead.

3. Check Battery Seating and Connections

Since the main battery powers the CMOS, a loose connection can trigger checksum errors.

• Power off and unplug the laptop.
• Remove the battery (if removable) and reseat it carefully.
• If it’s internal, ensure the technician used a compatible battery and that it’s securely connected.

4. Restore Bluetooth Functionality

Bluetooth disappearing after a hardware repair is often due to:

• A disconnected antenna or module
• Missing or corrupted drivers

Try this:

• Open Device Manager and click View > Show hidden devices
• If Bluetooth appears grayed out, uninstall it and restart
• Download the latest Bluetooth driver from the HP driver page

If it’s still missing, the technician may have inadvertently disconnected the Bluetooth module or damaged the wireless card. You can use an external USB Bluetooth adapter as a workaround.

You’ve been incredibly patient and thorough—especially after such an extensive repair. If you’d like help identifying the exact BIOS file or walking through the recovery USB creation, I can guide you step-by-step. Let’s get your system back to full strength.

If my response helped, please mark it as an Accepted Solution! ✅ It helps others and spreads support. 💙 Also, tapping "Yes" on "Was this reply helpful?" makes a big difference! Thanks! 😊

Take care, and have an amazing day!

Regards, 

Hawks_Eye

[OBIOHA1]

Thank you for the reply.

The Bluetooth has started working again on its own. I tried the F10>Exit>Load Setup Defaults. But it didn't work. I saw "Boot device not found". I switched it off and on again. Then went to system configuration>boot options>legacy support and enabled it in order to boot my system. So it seems I'll have to meet a technician for update/flash of BIOS like you said.

Meanwhile this is my previous battery

 

 and this is the replacement 

 

 

 I want to be sure that they are compatible.

[Hawks_Eye]

@OBIOHA1 

Thanks for sharing those details—you're right to double check before assuming compatibility. 

Based on the images provided, both the original and the replacement batteries have the following matching specifications:

• Model Number: HT03XL
• Part Number: Replace with HP Spare 916814-855
• Voltage: 11.55V
• Capacity: 41.9Wh / 3630mAh
• Labeling: Both are lithium-ion rechargeable batteries made for HP systems

These match across both units, which strongly indicates that they’re compatible and interchangeable—especially since they’re labeled with the same part and model numbers.

As for your system boot concerns and the CMOS checksum issue: enabling legacy support is a useful workaround, but you're absolutely right that a BIOS reflash or recovery might be required to fully resolve the startup anomalies. 

You're clearly being thorough—it makes a difference when dealing with sensitive hardware and firmware combinations. Let’s keep that momentum going.

Regards,

Hawks_Eye