# Zbook 15 G6 Undervolting locked



## Alyosha2001 (Feb 4, 2021)

Hello, this is my first post. I am a long time user of ThrottleStop for undervolting, and find it to be a gold feature for laptops. However, recently my laptop has been update to a newer BIOS, from October 19th 2020 (01.07.01). With this, both the undervolting and the fan control software (Notebook FanControl 1.6.3) have stopped working.
The only usable BIOS that allowed overclocking was 01.02.02, from October 9th, 2019. But I can't downgrade to it, because it does not allow to revert past the 01.05.04 version.
The laptop is a HP Zbook 15 G6, with i7-9850H CPU.
Are there any other users having the same issue? I saw that there is a fix for some Dell notebooks, to modify the locking bit, and I have tried it, too, but without success, as I am not savvy about that.
Huge gratitude to @unclewebb for this great utility!


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## unclewebb (Feb 4, 2021)

HP was one of the first manufacturers to start adding this fix to their laptops. I do not know how to go back to the previous BIOS version. Try the Notebook Review forum. There might be more users over there with your laptop model that have found a way to get CPU voltage control working again.


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## Alyosha2001 (Feb 4, 2021)

I will try the NotebookReview forum, thank you!


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## Alyosha2001 (Aug 8, 2022)

Any updates, yet? Meanwhile the NBR Forum has been dissolved, so I'm asking again, has someone else been affected by this and found a solution?


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