m15 R5, Bios update bricked laptop

With the AC adapter connected, press and hold power button for 30 seconds or until the light blinks.  It will reset Real Time Clock and may resolve the 2, 7 error code.

https://www.dell.com/support/kbdoc/en-us/000125880/how-to-reset-real-time-clock-rtc-to-recover-your-dell-portable-system

So the OS does boot on the LCD or added external monitor? If yes, open the Device Manager. Do you see an error on the GPU/video card?

@Chino de Oro​ Did nothing. Have already disconnected the battery regardless.

@DELL-Chris M​ Yes - there's no internal monitor, so the AMD Radeon Graphics Driver is error'd.

Forum Mods have posted many threads for users reporting of BIOS update issues.  You may want to visit the Alienware board (can not point you to specific thread since you failed to disclose the system information) and report the issue there.  If there is a bug in new BIOS release, there would be ten of thousand users flooding the forum, not just a few handful.  The new BIOS release, however, did break certain setup from users with Optimus and external monitors.  Work around option is downgrade to previous working version and waiting for more stable release next month.  Certain non-downgrade release will require using a bridge firmware by contacting Dell support.

Can't downgrade obviously, because it was a security update and dell doesn't allow it from within os and no way to see the screen from bios. So I guess it's just bricked by update.

Use the USB method.