When changing the SATA drive setting from RAID to AHCI, and disabling the "Secure boot" option in the BIOS (both actions are needed to install Ubuntu), the booting process gets stuck in the Dell logo for a long time, around 5 minutes, before it makes any progress. Even trying to enter the BIOS again to change those settings makes me have to wait that long.
Also, when booting when those settings on and entering the BIOS, the whole user interface of the BIOS menu, even just moving the mouse cursor around, is extremely slow. Clicking on a menu option on the BIOS makes the screen refresh to the next screen with a very slow transition of about 3 seconds.
I'm have upgraded to the latest BIOS firmware as of April 8, 2017 (Version 01.00.10, 3/9/2017). This bug is currently preventing me from setting up a dual-boot mode with Windows 10 + Ubuntu, which makes the system not usable for my specific use cases. I'd really appreciate if these issues could be resolved soon.
Thank you all in advance.