solved. another mistake in manual here:

HBM2 Example usage: ./amdmemtool -i 0,3,5 --faw 12 --RFC 208
GDDR5 Example usage: ./amdmemtool -i 1,2,4 --RFC 43 --ras2ras 176

-i should be --i

thanks for cool-tool! hope you share your new on-the-fly editor and hope it will accept CLI parameters.