Here's a mistake I found in your code:

2000 write:
Loopy_T = (Loopy_T&0xF3FF)|((val&3)<<9);

You are actually supposed to shift the val 10 to the left, like

Loopy_T = (Loopy_T&0xF3FF)|((val&3) << 10);

Still, I tried running smb1 with your mistake inserted in my code and I still got the title screen to be displayed correctly.

hydesprojects.cjb.net