@Rogue7
OTP CID is 51, but my EROM CID is 52. Could this be causing the problem?

No , your CID is 52 so you have correct files . Use XS++ for flashing and add MAIN & FS in
ADD section and CUSTPACK unpack and put folder "tpa" in XS folder "own custpack".
In XS++ in section customization select "own custpack" and when you have all this done press flash (that should be work)