Dual Language FFV?

[DNSDies]

I'm trying to turn a retail cart of FFV into a switchable dual-language cartridge by leaving the cart in normal shape and soldering a TSOP package under one of the existing mask roms.

Now, I know I need a decoder to make this work, as the cart (SHVC-2J3B-01) has 2 mask rom slots, sram, and a built-in 74LS139 and 74LS00.

Is there any way to use these built in decoders, or will I need to add an additional 74LS139 and tie it to the 74LS00 and switch the original mask rom lines on/off when I want it in english?

[Markfrizb]

I'm trying to turn a retail cart of FFV into a switchable dual-language cartridge by leaving the cart in normal shape and soldering a TSOP package under one of the existing mask roms.

Now, I know I need a decoder to make this work, as the cart (SHVC-2J3B-01) has 2 mask rom slots, sram, and a built-in 74LS139 and 74LS00.

Is there any way to use these built in decoders, or will I need to add an additional 74LS139 and tie it to the 74LS00 and switch the original mask rom lines on/off when I want it in english?

I would think that you could double the roms and just tie your switch to the CE (chip enable) lines to select between the 2 versions. No additional decoder's would be needed.