XPS 14 9440 BSOD (kernel mode heap corruption / kernel security check failure) after upgrading BIOS to 1.12.1

Dear community,

Since I have upgraded my BIOS to version 1.12.1 (Previsous was 1.11) I am having multiple random BSOD tipically with messages like kernel mode heap corruption or kernel security check failure.

This seems to hapen more times when I am using the laptop without my dock (dell official dock).... this is more strage....

I have been using my laptop for 3 months with 0 problems.... and now I am having this problems....

Options:

- New BIOS versión has a BIG bug

- Laptop has a failure... this is strange becouse it has start happening just after upgrading...

What have I tried:

1. I have tried downgrading the bios (downgrade capability is enabled in bios) but the systems shows a warning with downgrade blocked for this version. I have tried to install previous version from windows and also using "rcv" file from BIOS Flash Tool with same result (downgrade blocked).

2. I have tried a clean SO install

3. With or without updating drivers from dell support web

4. Basic and Advanced diagnostics from bios with no errors reported

Is there a way to "force" downgrade ¿? Is there any problem already reported with this BIOS version ¿? Is there anything that I can try ¿?

Meny thanks in advanced.

Jose Manuel