Update Dell BIOS from linux

NOTE: messing with your BIOS is obviously dangerous.  Proceed at your OWN RISK!
First, install libsmbios-bin

sudo apt-get install libsmbios-bin

Now, you need to get the proper .hdr file.  It is bundled inside those little executables Dell has on their website.  So, start by downloading the latest .exe file from Dell. These can be extracted either with unzip or wine, as shown from this log file.
After trying unzip, I tried this command, and it worked:

wine O780-A13.exe -writehdrfile -nopause

Creating the file: O780-A13.hdr Now, follow these directions (as su or root):

modprobe dell_rbu
dellBiosUpdate -u -f ./O780-A13.hdr

Now just reboot, and wuala, an updated BIOS.