M7710 with failed battery, unable to update Thunderbolt firmware

Hello 

I have an issue that cannot update the firmware for the Thunderbolt ePort TB16, and its because the battery is not connected. The battery is on the laptop but due to damage to the battery circuit (as read on another blog), the laptop does not charge nor drain from the battery. My laptop is out of warranty, so I will not get a new one for the moment. 

I need to update firmware as I am not able to use the USB ports on the TB16 neither the Ethernet cable. Reading in the support pages, the latest firmware needs to be updated for this to work. 

How can I install the firmware updates 'without a battery" ? is there any work around, or this issue is a lost battle? 

Thanks