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  1  1  1  1  X  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  X  1  1  1  1  1  1  1  1  1 a^5*X  1  1 a^2*X  1  1  1 a^3*X  1  1  1  1 a^4*X  1  1 a^6*X  1  1  1 a*X  1  1 a^4*X  1 a^4*X  1  1  1  1  1  1  1  1  1  1  1  1 a*X  1
 0  1  1  a a^6*X+a^2 a^3 a^6*X+a^4 a^5 a^6*X+a^6  a a^6*X+a^2 a^6*X+a^4  1  0 a^3 a^6*X+a^6 a^6*X+1 a^5 a^6*X+a^6  a  1 a^6*X+a^4  0 a^6*X+a^2 a^5 X+a^3 a^6*X+1 a^5*X+a^2  X a^3  1 X+a^3 X+a  X a^5*X+a^4 X+a^5 a^5*X+a^6 a^5*X+a^2 a^4*X+a^4 a*X+a a^6*X+1 a^4*X+a^6  X a*X+a^5 a^5*X+1 X+1 X+a^5  1  a a^5*X+a^6 X+a^5 a^4*X+a^2 a^5*X a^4*X+a^6 a^2*X+a^3 a*X+a a^3*X+1  1 a*X+a^5  0  1 X+a a*X+1 a^2*X+a^6  1 a^3*X+a^2 a^5*X+a^6 a^2*X a^5*X+a^4  1 a*X  1  1 a^4*X+a^6 a*X+1 a^4*X+a  1 a^3*X+a^3 a^4*X  1 a^5*X+a^2  1 a*X+a^5 X+a^2 a*X+a^2 a^2*X+a a^4*X+a a^3*X a^3*X+a^4 a*X+a^5 a*X a^2*X+a^2 a^2*X+a^6 a^5*X+a^4  1  0
 0  0 a^6*X  0  X  X a^3*X  X a^2*X a^3*X a^6*X a^2*X  X a^4*X a^5*X  0 a^6*X  X a^5*X a*X a*X a^4*X a^3*X  X a^5*X a^6*X a^5*X a^5*X a^4*X  X a^4*X a^4*X a^4*X a^5*X a*X a^5*X a*X a^2*X a^2*X  0  0  0  X a^5*X a^3*X a^4*X a^4*X a^4*X  X a*X a^3*X a^5*X a^6*X a^4*X a^6*X a*X a^4*X  X a^2*X a^3*X a^2*X a^4*X  0  X a^2*X a^3*X a^5*X a^5*X a*X a^2*X a^2*X a^3*X a*X  X a^3*X a^5*X a*X  0 a^4*X a^6*X  0  0  X a^2*X a^3*X a^3*X  X  0  X  0 a^2*X a^6*X  0 a^3*X a^4*X  0
 0  0  0  X a^6*X a^5*X a^3*X a^2*X a^5*X a^6*X a^6*X a^6*X a^5*X a^3*X a^3*X a^2*X a^2*X a*X a^2*X  X  0 a^4*X a*X  X a*X a^4*X  X a^6*X  0 a*X a^6*X  X a^3*X a^4*X a^4*X  0 a*X  X a^3*X a^4*X  X a*X a^5*X a^2*X a^3*X a^5*X a^6*X a*X a^6*X a^5*X  X a*X a^3*X a^5*X a^3*X a^2*X  0 a*X a^6*X a^5*X  0 a^4*X a^4*X a*X  X a^2*X a^6*X a^2*X a^3*X a*X a^4*X a^5*X a^5*X a^2*X  X a^3*X a^6*X a*X a^6*X a^5*X a^2*X a*X a^3*X  0 a*X a^5*X a^2*X a^4*X a^5*X a^5*X a^3*X  X  X a^6*X  0 a^2*X

generates a code of length 96 over F8[X]/(X^2) who´s minimum homogenous weight is 640.

Homogenous weight enumerator: w(x)=1x^0+154x^640+896x^646+56x^647+840x^648+1456x^650+3696x^651+5096x^654+1568x^655+3038x^656+6664x^658+11144x^659+9184x^662+4368x^663+5376x^664+11592x^666+18312x^667+14448x^670+11424x^671+12047x^672+22680x^674+33432x^675+19040x^678+11256x^679+10241x^680+14952x^682+19432x^683+8680x^686+322x^688+196x^696+161x^704+147x^712+77x^720+70x^728+35x^736+42x^744+21x^752

The gray image is a linear code over GF(8) with n=768, k=6 and d=640.
This code was found by Heurico 1.16 in 24.7 seconds.