I answered in of your many posts (removed and understanbly, you still have 9 of them about this issue, who knows how many removed ones?!!?!) about the first program found by Google on github that would convert these images. What does that do?
You won't be able to blindly modify a corrupted block so it doesn't blow up some decompression algorithm in a program where you have only the binary for the program. But with an open source program, first of all it might not crash, and even if it does you'd be able to see the line and edit it to not crash or give up when something isn't the expected value.