I figured out how to do it using a USB stick so it's up-to-date now, even if I never figured out the original issue.
Trying to update BIOS on my Inspiron 15 Gaming 7567 to 1.15.0.SupportAssist fails, both on my desktop and on dell.com. Tried manual installation, but when I click on the downloaded .exe file nothing happens. (Running it both regular and "run as administrator") Any idea what might be wrong or what I should do next? Not running BitLocker and only virus software is Windows Security. 
BIOS won't update - 15 7000 (7567)