I recently started working on my own romhack of "Super Mario Bros" using the NTSC-U/C version of the game. I finished making the first three levels without any problems but once I got to 1-4 (The first castle) I encountered a major issue.
The beginning of the level was supposed to start with some simple jumps over pits with podoboos and around firebars. After sorting the level into the first slot so it would be easy to test I loaded it in the Bizhawk emulator and to my surprise the podoboos and firebars were all in the wrong spots. They were certainly not in the spots I placed them or the spots they were in the original game. I was puzzled by why such a problem would happen but I thought it might have to do with moving the level to the first spot, so I moved it back to the original 1-4 position, played through the first three levels I made, but when I got to the castle the podoboos and firebars were still messed up in the same way they were before. Unfortunately I could not come up with any other ideas to why this problem would occur so I decided to look it up on the internet to no avail. My last chance was to come here and ask someone who hopefully has more SMB romhacking experience than I do for an answer to this problem.
I know the previous paragraph was a little long but I wanted to explain the problem and my efforts to fix it in the most imformative way I could.
Thank you for looking into my problem.