You could try flashing the unlocked BIOS but it's not suggested to skip that many versions in one go as you could brick the system so flash at your own risk. It may let you bypass the battery issue though.
The other option is using the BIOS recovery method. To do this you need to extract a specific file from the BIOS version you want, rename it M17R3.hdr and put it onto a Bootable USB drive (using RUFUS). Then you stick the drive into the eSATA port, remove the battery and power adapter, hold the end key down while plugging in the adapter only (no battery). Then wait until it forces a flash which can take up to an hour. This is usually only done when a 1 Beep error occurs to fix a BIOS corruption.
If you try any of this it is at your own risk. BIOS flashing and recovery does not always go to plan and can make things worse if it fails. It's usually a last resort thing.
I just happened to read this posting. I'm commenting because I have a M17XR3 that I've successfully flashed to its latest BIOS. It isvery important to use your Service Tag to download the proper BIOS file from Dell rather than model numbers when flashing your BIOS. This will help to eliminate the possibility of unexplained errors during BIOS flash attempts. The model numbers can be confusing from one model year to the next. Also, the Dell support site is the only place where you can safely download a BIOS file.
MattB79 gave you some good advice. By the way, what made you determine that you needed to risk bricking your machine with a BIOS flash?