Using dcu-cli to install bios updates

Hi, I need some advice on writing a script which installs BIOS updates on Dell notebooks (Latitude 5510 and others) with BIOS passwords set.

Here's my approach:

...

"c:\Program Files\Dell\CommandUpdate\dcu-cli.exe" /configure -autoSuspendBitLocker=enable -biosPassword=%BPWD% 
"c:\Program Files\Dell\CommandUpdate\dcu-cli.exe" /applyUpdates

...

which seems to have a flaw since although the BIOS update is found an installed under Windows on reboot Bitlocker doesn't deactivate and the BIOS flash install doesn't start.

Thanks a lot for your input!