If you've got a PLED (did i remember correctly?) then it might *say* that it's 4-bit compatible, but many are not - including Wilba's and mine - which is why Wilba made this 8-bit driver. If you have a different LCD it might be the same :( If it didn't work in 4-bit mode, then it doesn't work... Edit: When you ran in 4-bit mode, you had the four unused pins on the LCD itself and also the core LCD socket, connected to nothing, right? If you used an 8-bit style cable with the 4-bit LCD that might explain your problem. Well you won't **** the hardware up, so if you have a working copy of the firmware, then just copy it, and work on the copy. If all else fails, you can roll back to the original :) MIOS has a great feature where the ID of the PIC will select a certain driver. You just have to tell the assembler (GPASM) to build that driver into your hex file. The MB6582 package contains the custom driver that Wilba made. Just find the section in the file. Use the search, you'll find it :) Which ones? We'll fix em up. You worry too much :) You will find once you try it, that it's not as hard as it sounds (or sometimes, that it really is as easy as it sounds, even though you didn't think it would be) Edit: have you searched the forum for 4-bit LCD yet?