CMOS Checksum Invalid (502) on boot, even after replacing CMOS battery

[BadChecksum]

Hello, my problem is with a HP 24-e014 All-in-One Desktop PC with product SKU Z5N92AA running Windows 10 Home Edition (64bt).  

Recently it has started booting slowly and/or when this happens, before it will boot into Windows, the HP firmware displays the message I placed in the post title, which is similar to "The CMOS Checksum is invalid (502)" error.  I took a picture of the BIOS system log which shows the 502 errors occurring, but I can't seem to interpret the timestamps, maybe someone could help me with that as well.  

Anyways, I followed the instructions on https://support.hp.com/us-en/document/c04126730 for generic reset of CMOS, since the product page for Z5N92AA does not appear to list specific steps as described.  

This entailed me removing the base, opening the case as gently as possible, and removing the old CR2032 3V battery and replacing it with a brand new energizer brand battery of the same type and voltage.  I held the power button down at various steps to clear the CMOS data as described in the article.  After booting it gave me the 502 error message one more time, and then it seemed to boot normally, but now the next morning, the 502 error message is coming up again.  

It seems like maybe the power is going out at some point in the night which is causing the CMOS data to reset?  Or it has nothing to do with that and it's actually a software issue?  

Does anyone have any experience with this?  It's extremely aggravating.  I would just disable the **bleep** checksum feature myself if I knew how.  The device is out of warranty according to HP Smart Assistant.  

Thank you in advance.  Two images of BIOS will follow.  The first does not show the latest 502 error as I took this picture after replacing the battery.  I have not taken any photos since.  

BIOS System Log

[itsmyname]

@BadChecksum -- due to the bad values in the CMOS, the date/time values default to 01/01/2009 and 00:00:xx or 00:01:yy (hours/minutes/seconds).

It is rare for the CMOS chip to "fail", but, of course, nothing is impossible.

Are you inserting the replacement battery with the etched lettering "visible" ?

Hopefully, your replacement battery is not a "dud" battery.

How old is the motherboard? Years? If it is less than one year, exercise the HP Warranty to get the motherboard repaired/replaced, at HP's expense.

[BadChecksum]

Thanks for your reply and explaining the timestamps.  

It's kinda bizarre that the BIOS shows the correct date normally though, like in my screenshot.  Erm, ok for some reason that screenshot is gone now.  It says image rejected?  Anyways.  

I'm not sure what you mean by with the etched lettering visible, but the positive terminal + is facing up and the negative one is facing down, just like the battery before it, which was the original battery.  

I don't know why tbe battery would be a dud, I could try another one but two others from the same packaging have worked perfectly fine.  

As I said before, the machine is out of warranty.  Are you referring to a motherboard-specific warranty?  I couldn't tell you exactly how old the board itself is, but it's definitely not less than 1 year old.  ☹️

Is there any way to get HP to weigh in on this?  There is definitely something suspect with their BIOS/firmware, as I had another HP laptop that is only about a year old throw the same 502 checksum error around the middle of October, but it's totally fine now.  

I would really prefer to disable the stupid checksum comparison.  It's just a pain in the ass ultimately when it's backfiring like this.  

[itsmyname]

@BadChecksum -- I'm not sure what you mean by with the etched lettering visible:

Sample image:   xc004.webp (500×500) (tenaquip.com)

of the etching.

>  I could try another one but two others from the same packaging have worked perfectly fine.  

I recently removed the 2 AA batteries from my smoke-detector, because it did not signal anything when I pressed the "test" button. Both batteries were installed, a year ago. One of them was totally corroded, and tested at 0 Volts & 0 Amperes. The other one tested at 1.5 Volts and 4.1 Amperes -- still "good".

A brand-new battery (same manufacturer and same lot) tested at 6.2 Amperes -- excellent!

So, in my case, one battery was a "dud".

> but it's definitely not less than 1 year old.  

In that case, the original one-year HP Warranty should still be active.

Is this your computer: HP 24-e014 All-in-One Desktop PC Product Specifications | HP® Customer Support

This model was released in August 2017.  So, on what date was your computer factoroy-assembled?

Note that the start-date for the warranty could be the date that it was manufactured.

If you did the "online registration", the start-date for the warranty should be reset to the date of the registration (or the date of purchase, if the registration asked for that information).

> Is there any way to get HP to weigh in on this? 

This is a user-to-user discussion forum, although a few HP employees do participate.

I recommend that you make an official contact with HP Support, especially if the warranty is current.

[BadChecksum]

Hey thanks again for replying. 

Based on your image, yes the battery has the + terminal and the "etching" facing upwards, just like the original battery.  

For all of those hard at work to resolve this problem on their own time, it may help you to know that I tested the original (old) battery and a brand-new battery from the same packaging and they both read the same on DC voltage (3.2) and mA (0.12) functions.  So, it would seem that the battery was fine and not the cause of the problem, which makes sense because changing it did nothing.  

Ok, so I posted an image that had all of this information but for some reason the forums deleted it I guess?  Anyways, here goes again:

Product Name: HP All-in-One 24-e0xx

SKU Number: Z5N92AA#ABA

System Family: HP Desktop

Born on Date: 03/20/2018

System Board ID: 82DD

System Board CT #: PGAVK0A8JAF4HG

BIOS Revision: 82DD vF .50

BIOS Date: 04/24/2019

Processor Type: Intel(R) Core(TM) i3-7100u CPU @ 2.40GHz

Memory Size: 8192MB DDR4 / 2133MHz / Single Channel

To clarify, when I said that the board is definitely NOT less than a year old I meant that because it is WAY OLDER than 1 year.  

Again, according to the HP Support Assistant app or whatever it's called, the machine's warranty is expired.  It's "Born Date" is 03/20/2018.  

I repeat, the warranty is NOT current.  It is expired.  

The https://support.hp.com/in-en/document/c05663990 link you provided is in fact the correct machine, yes.  

I'm trying to find out if there is a BIOS update that would fix this issue.  Is it possible I should be looking instead for a UEFI update?  Is it even possible to update the UEFI?  Are they one and the same?

Also there is only one (1) BIOS update that I can see for this 82DD board, and it is dated 2018, when my current BIOS  version says 04/24/2019.  How could the "recovered" BIOS revision be newer than the latest release?  The revision vF .50 isn't even in the revision history on the website.  Oh lord.  

Searching the forums for similar issues has proved futile (regarding viable answers) and I am running out of options here.  😅

[itsmyname]

@BadChecksum -- How could the "recovered" BIOS revision be newer than the latest release? 

It is possible that HP made an "engineering change" (EC) to the motherboard.

So, the older BIOS (on their web-site) will work with both pre-EC and post-EC motherboards, while your post-EC motherboard has a post-EC BIOS that is not compatible with the pre-EC motherboard.

Maybe.