ZBook 15 Gen I BIOS Downgrade from 1.36 to 1.34 not possible

[SieglindeFest]

I did an BIOS - Upgrade via Network from L70 1.34 to new BIOS l70 1.36

Now i want to downgrade / rollback to BIOS 1.34 but the update-utility encounters an error with "bios file specified did not pass validation"

Are there any restrictions in the BIOS 1.36 so that isn´t possible to downgrade?

i can´t seem to find the file 1.36 on the support site for ZBook 15 Gen. i. Only by using the Update by Internet, this file is offerd. What is reason for this?

Best Regards from Michael Graf

[REO51ST]

@SieglindeFest

To better help you we would need the exact model number or product number of your laptop/desktop???

http://h20564.www2.hp.com/hpsc/doc/public/display?docId=emr_na-c00033108

REO

[SieglindeFest]

The Number is D5H42AV

Do you need the serial-Number?

Best Regards

[REO51ST · Accepted solution]

@SieglindeFest

This is what I found.

01.36 Rev.A(8 Nov 2016)

Provides improved security of UEFI code and variables. HP strongly recommends transitioning promptly to this updated BIOS version which supersedes all previous releases. NOTE: Due to security changes, after this BIOS update is installed, previous versions cannot be reinstalled. 

REO

[SieglindeFest]

Thank you, my question is answered.

Best Regards

Michael Graf