BIOS problem with version F.35 Rev.A

[Ovi9]

Hi all,

I have a HP ZBook 15v G5 Mobile Workstation with SN: [Personal Information Removed]
I've done before many BIOS Update without problems, but 2 months ago
on power(but battery was at 48% healthy) and from Windows 10 started
with HP Utility BIOS Update with the version    F.35 Rev.A.
It started normally and at 70% came black screen and run it forever.
After 3 hours wait, I stop it.
Then enter in a boot loop with INFO 500 and 502. Also, with CAPS LOOK blink 2 long and 2 shorts.
Trying to reflash with USB bootable HP Solution work without success:

1.Startet to write BIOS (only with version F.35 and F.34, with older than F.34 even didn't started because HP protection).
2.Than make checksum verification I see only from 50% maybe is too fast.
3.Than goes until 100% but reset button is deactivated and decremental counter is frozen.
4.After some minutes make a shutdown.

Then the never-ending story...

Trying to reset CMOS with Win Taste + C comes just a Info that BIOS will be reseted but after a new start goes in BIOS problem again.
I didn't find that this model has a CMOS battery on HP site or another. Could someone confirm that ?

I will be thankful for any information in order to recover my laptop. I could for the moment just hope that with a new BIOS Version from HP when will be
arrive my problem will be solved.

Anyway, I don't trust anymore to make a BIOS update because this unreliable mechanism.
And if HP count that with that BIOS update make me buy another HP laptop (my HP ZBook 15v G5 Mobile Workstation costs 1500 euro) is totally wrong. Sorry but no
and also, will not recommend to many friends of mine HP anymore.
In my opinion this is the second worst failure issue after losing personal data.

Best regards,
Ovi