ROM Hack how to convert 128kb vba save to 64kb for use in GBA VC

[noctis90210]

I have several save backups on my pokemon emerald using VBA emulator...
it produces 128kb save file which is not compatible for injecting it into Custom GBA VC that only needs 64kb save file...

how can i convert 128kb save file to 64kb?

i tried changing the settings on VBA 1.7.2 :

Test #1
Settings: rtc checked + 64kb save file checked
Output: game doesnt boot

Test#2
Settings: rtc checked + 64kb save file checked + import 128kb battery file
Output: game boots, but when saving... still remains at 128kb

is there any solutions?
thanks and have a nice day...