The generator matrix

 1  0  1  1  1  1  1  1  1  1  1  1  0  1  1  1  1  1  1  1  0  1  1  1  1  1  2  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  2  1  2  1  1  1  1 2a+2  1  1  1  1  1  1  1  2  1  1  1  1  1  1 2a  1  1  1  1  1  1  1
 0  1  1  a 3a^2+2 2a^2+3a+1 a^2+3a a^2+3a+3 3a^2+2a+3  a 3a^2+2 a^2+3a  1  0 2a^2+3a+1 3a^2+2a+3 2a^2+3 a^2+3a+3 3a^2+2a+3  a  1 a^2+3a  0 3a^2+2 a^2+3a+3 2a^2+3a+3  1 2a^2+3 3a^2+2a+2 2a^2+3a+1 2a^2+3 3a^2+2a+2 2a^2+3a+3 2a^2+2a+1 a^2+a a+2 a+2 a^2+3a+1  2 a^2+3a+1 a+2 3a^2+2a+2 2a^2+3a+3 2a^2+2a+3 3a^2+a a^2+a+2 3a+1 a^2 2a^2+3a  1  2  1 a^2+a 3a a^2+3a+2 3a^2+2a+2  1 2a^2+3a+3 3a+1 3a a^2+a+1 3a^2+3  a 2a^2+a+1  1 2a^2+a+2 3a^2+3a+3 2a^2+1 a+2 a^2+3a+1 2a^2+3  1 3a^2+a 2a^2+2a+3 3a^2+2 a^2+2a+2 a^2+a+1 a^2+3a  0
 0  0 2a^2+2  0  2  2 2a+2  2 2a^2 2a+2 2a^2+2 2a^2  2 2a^2+2a 2a^2+2a+2  0 2a^2+2  2 2a^2+2a+2 2a 2a 2a^2+2a 2a+2  2 2a^2+2a+2 2a^2+2 2a 2a^2+2a+2 2a^2+2 2a^2+2a 2a^2+2a 2a^2+2a 2a^2+2a  0 2a^2  0 2a+2 2a^2 2a+2  0  2 2a+2 2a^2+2a+2 2a+2 2a^2+2a+2 2a^2+2  0 2a^2+2 2a^2  2  0  0  2 2a^2+2a 2a^2 2a^2+2a+2 2a^2+2a 2a^2 2a^2+2a 2a^2+2a+2 2a^2 2a 2a^2+2  0 2a^2+2a+2 2a^2 2a 2a^2+2a+2 2a^2+2a  0 2a+2 2a^2+2a 2a^2+2a+2  0 2a 2a 2a^2+2a+2 2a^2+2  0
 0  0  0  2 2a^2+2 2a^2+2a+2 2a+2 2a^2 2a^2+2a+2 2a^2+2 2a^2+2 2a^2+2 2a^2+2a+2 2a+2 2a+2 2a^2 2a^2 2a 2a^2  2  0 2a^2+2a 2a  2 2a 2a^2+2a 2a+2  2 2a 2a+2 2a^2+2a+2  0  2  0  0 2a^2+2 2a^2+2a 2a+2 2a+2 2a^2 2a 2a^2+2a+2 2a  2 2a+2 2a^2+2a 2a^2+2a 2a+2 2a 2a 2a  2  2 2a^2+2a+2 2a^2+2a+2 2a^2+2a 2a^2 2a+2 2a^2+2a 2a^2+2a 2a^2+2a 2a 2a 2a^2+2a+2 2a^2  2 2a+2 2a^2+2 2a^2+2 2a^2+2 2a^2+2 2a^2+2a+2 2a^2  2  2 2a^2+2 2a^2+2a 2a^2+2a+2  0

generates a code of length 79 over GR(64,4) who´s minimum homogenous weight is 520.

Homogenous weight enumerator: w(x)=1x^0+84x^520+56x^525+336x^527+504x^528+1232x^530+2240x^531+2072x^533+1344x^535+798x^536+8288x^538+9744x^539+5544x^541+3808x^543+756x^544+16128x^546+17808x^547+16968x^549+8512x^551+504x^552+34720x^554+33712x^555+26880x^557+14672x^559+378x^560+25648x^562+22512x^563+5824x^565+217x^568+245x^576+231x^584+161x^592+77x^600+84x^608+49x^616+7x^624

The gray image is a code over GF(8) with n=632, k=6 and d=520.
This code was found by Heurico 1.16 in 19.4 seconds.