Assigning 4 colors to a tile with no transparency?

[winteriscoming]

Is it possible to assign 4 colors to a tile with no transparency?  It appears that editing the palette color associated with the transparency has no effect.

There are block tiles that do not need transparency that might ideally use 4 colors instead of being restricted to 3, with the assumption that 1 is transparent.

Anyone know if this is possible?

[sodthor]

Unfortunately, I haven't found a way to do it. I was looking for a system register to disable transparency but if it exists it does not seem to be documented.

[winteriscoming]

Unfortunately, I haven't found a way to do it. I was looking for a system register to disable transparency but if it exists it does not seem to be documented.

Thanks.  That's unfortunate.  Just one more color on some tiles would make them look that much better.  I suppose the next best thing is to plan for transparency with an expected BG color.  With hblank interrupts, you could assign a BG color per tile row.  That can get complicated if you need the BG color to be something like a light color because of non-block tiles in the same row, and the block tile ideally would have it be a dark color.  

I guess I'll stick to 3 color tile blocks for now.