It's a very, very bad idea - if the flash fails due to a power interruption, you'll be out the cost of a mainboard.

Replace the battery, charge it fully and THEN flash.

It looks like the short answer is NO!  The Bios install program is written to require a "detectable battery" (detectable by the older bios) even if it is the older BIOS that is itself bugged and cannot recognize a fully specificationally functional battery. 

LOL, are these programmers smart or what?

I wanted to update my Latitude D820 bios when I got an error saying that the battery must be at 10%.  I find this a strange requirement.  What about updating BIOS for desktops?  Does it require a battery backup do update the BIOS?

Pretty soon, Dell will make it say battery must be at 20%, then 30%, then . . .

LOL, don't give Dell any ideas about adding battery backups to Desktops. 

Which brings me to ejn63's reply: "It's a very, very bad idea - if the flash fails due to a power interruption, you'll be out the cost of a mainboard."  My question to him and del is: So how may desktop mainboards have been fried during bios installs?

 You don't fry the board from a bad flash but you may end up having to buy and replace the EEPROM chip which is or should be extractable and replaceable for a lot less than a new board; usually around $30. Most companies will flash the BIOS to the new chip for you before shipping if you send them the flash file. The truth is it's a bad idea to need a battery installed in a laptop to get your work done. Lenova is losing business by the droves because they engineered this in their requirements. This is just Dell trying to cover their A's from bad flashes but anyone that has read on the subject knows that flashing a BIOS is a risk and sometimes they go bad regardless of the power supply.A BIOS is just like any other software, it's subject to corruption. Unfortunately you don't know it's corrupted until you reboot and realize the computer is dead but the motherboard isn't bad it's just a chip that contains corrupted software. The problem is that you can't fix it because it's the software that starts everything and the computer is dead in the water without that software working. As far as I know there is no way to clear a chip from a bad flash but you can buy new ones.

The BIOS chip is soldered to the system board - it will cost a lot more than $30 to have it replaced.

If Lenovo (note your incorrect spelling) is losing business, then why has it reported a profit once again?

The BIOS is firmware, not software. 

The only correct information above is that there's no way for an end user to recover a bad flash.

Hi, i think this post may be out of time but i hope you find this usefull.

The answer is YES i already done with a Dell 6400 (Latinoamerican version of E1505).

There are few simple steps to do the upgrade with a USB Pen drive.

1. Download unetbootlin for operating system.

2. Once download choose from the Distro menu FreeDOS and create the disk (please be sure to format the USB in FAT32 before create the disk)

3. Download and copy the bios upgrade program to the memory ( The MMXXXX.exe) file.

4. Boot from USB and choose the option 2 from FreeDOS called Safe Mode

5. Now your under a DOS envieroment, move to c: by typing c: (intro)

6. Now just type the name of the program you want to run like c:>MMXXXX.exe /forceit (intro)

7.Follow instructios( type y) and finally it will reboot the system, and... you upgraded the bios.

If you found any problem, ask me.

This posts show the way to get ride with this problem.

I had to get a new bios chip put in today. Cost $95.

You don't fry the board from a bad flash but you may end up having to buy and replace the EEPROM chip which is or should be extractable and replaceable for a lot less than a new board; usually around $30. Most companies will flash the BIOS to the new chip for you before shipping if you send them the flash file. The truth is it's a bad idea to need a battery installed in a laptop to get your work done. Lenova is losing business by the droves because they engineered this in their requirements. This is just Dell trying to cover their A's from bad flashes but anyone that has read on the subject knows that flashing a BIOS is a risk and sometimes they go bad regardless of the power supply.A BIOS is just like any other software, it's subject to corruption. Unfortunately you don't know it's corrupted until you reboot and realize the computer is dead but the motherboard isn't bad it's just a chip that contains corrupted software. The problem is that you can't fix it because it's the software that starts everything and the computer is dead in the water without that software working. As far as I know there is no way to clear a chip from a bad flash but you can buy new ones.