Hello, You board has same GPIO base addr so the trick might work too. Because I dont know how to force isadump to dump only one byte I made some program that could do the trick for you. We dont know if this would work. In general it is not good to play with GPIO when we dont know what they doing but the risk is sometimes gain :) #include <sys/io.h> #include <stdio.h> int main(void) { unsigned char val; iopl(3); val=inb(0x4B9); printf("Was %x\n",val); val&=~0x4; //clear bit 2 val|=0x8; //set bit3 outb(val,0x4B9); printf("Wrote %x, readback %x\n",val,inb(0x4B9)); return 0; } gcc trick.c -o trick su ./trick I would like to see the i2cdump (or if you have recent sensors-detect you can try it also) and dump of this program. Thanks Rudolf