Need help with decompressing and compressing overlay files

[MackanK]

I have tried to make some changes to the type effectiveness chart in the Generation 5 games. I have thoroughly gone through the other threads and posts on this forum that details how to do this, and have tried using many different programs, such as Crystal Tile 2, Batch LZ 77, dsbuff, and dslazy.

I think I understand how to make the actual change, in theory, but as I have been unable to get the file to work I don't know. Regardless, the problem now is that I can't correctly compress or decompress the overlay file.

This is how the programs have worked so far; CT2 is the only one that can decompress it in such a way that the correct type effectiveness code is visible, but I can do no more with it. BLZ looks like it could work but right now there seems to be something wrong with its functions and I always get an error when trying to decompress telling me that the file isn't compressed.

Dsbuff and dslazy can extract the files but not decompress them in such a way that the right code can be edited, and I also can not compress the file with them. I have searched on the internet for solutions to the BLZ error and tried various things, but none of them have worked.

I would really like some help with how to get the (de)compression parts working, I have really tried getting it to work on my own but I just can't solve it. Any help is appreciated, thanks a lot!