ROM Hack Need help changing a snes vc cia header

[Ampersound]

I've recently noticed that my injected Earthbound sometimes has distored sound and realized that the cia header is at fault, based on the information here:
https://www.3dbrew.org/wiki/3DS_Virtual_Console#data.bin_structure

Now i'd really like to change the audio in the cia header so it's identical to the original version of earthbound on VC. The thing is, I also wanna keep my savegame as i've been playing it for a while.

Is it possible to change the header of an already encrypted game title?

What would be the best way to go at it?

Thanks for your time

 

[RandomMan25XX]

reinject the rom with NSUI, that may fix your sound issue, if you've already used NSUI to inject in the first place then please modify the sound levels in NSUI's options

 

[Ampersound]

Did a backup with checkpoint and tried to install over the old file with an .smc rom. Didn't work.
Then i uninstalled it and tried it with the .sfc version, and it worked.

Now idea if the sound issue is fixed because apparently checkpoint deletes your saves when you uninstall something. great

 

[Ampersound]

Ok the savegame is still saved.
Injecting it again with NSUI at 100% volume doesn't change the sound distortions