The generator matrix

 1  1  1  1  1  1
 0  2  0  0  0  2
 0  0  2  0  0 2a+2
 0  0  0  2  0  2
 0  0  0  0  2 2a+2

generates a code of length 6 over GR(16,4) who´s minimum homogenous weight is 8.

Homogenous weight enumerator: w(x)=1x^0+45x^8+120x^12+315x^16+3072x^18+360x^20+183x^24

The gray image is a code over GF(4) with n=24, k=6 and d=8.
This code was found by Heurico 1.16 in 0.0028 seconds.