Why do you want to update the BIOS?
You don't need to update the BIOS, as far as I know, if you don't have a problem with your stick.
If you want to update it, however, You should check the BIOS file is fit to your stick, not x86 or x64, but T07 2G version or T07 4G version. There is no x64 or x86 BIOS difference in the Resources section.
If you want to use 32bit capable operating system, then install 32bit O.S. like Windows 10 32bit, or want to use 64bit capable O.S., then install 64bit O.S.
x64 or x86 is up to the O.S. not to BIOS.