During my firmware update using my iPhone 7 Plus the battery went dead (I installed the wrong battery) and now I have a constant red led and the firmware number says unknown in the settings?

Help!!!!

May I know which Osmo you own? Osmo, Osmo+ or Osmo Mobile?
If the right LED is solid red, please try to wipe the copper sheet inside the battery compartment with 95% alcohol and cotton swab. Let the alcohol air dry. If it does not work, wipe the battery contact with alcohol and cotton swab.  
Please keep me updated if the problem persists after that.

you install the wrong battery?  I could not get it.