The issue in the bootcamp Windows partition is not from the wrong Firmware update, I think.
The B03 will not install, whatever you do.
Also you cannot roll backnormally to an earlier Firmware version, after a correct update.
I strongly advise not to mess with the system unless you know exactly what you are doinbg, and know exactly what to do when you end up with a corrupted system.
Questions: how do you know what the Firmware version is now? Who told you to use Firmware update B03? And why? And what makes you think that B08 is corrupted? Why has the "corrupted" B08 anything to do with a third party battery from China? What Windows version did you install in the Bootcamp partition?
The only thing I can imagine happened is that the Windows drivers in Bootcamp are not correct for the Windows you wanted to install or are corrupted.
Can you open SystemInformation (in Applications/Utilities/) and make a screenshot of the information on the right side (blank out the serial number).