Dell recently posted a new BIOS for the M11x R3 on their support site - A05.
Grab it here: M11x R3 - BIOS A05
Release notes:
Since that's only half the fun I also unlocked the hidden menus, see attachment.
As always with modified BIOS - use at your own risk, don't change anything you aren't familiar with.
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M11x-R3_A05_[unlocked].zip&