Generate Random Matrix whose Determinant is relatively prime to 128

I need to generate a random matrix whose determinant is relatively prime to 128. If the GCD(Determinant, 128) is not one then it should generate another random matrix of size nxn.

I have done this but I am missing out on some part. The issue I am facing is, when the GCD!= 1 it generates another new random matrix, instead I want it to override the previous randomly generated matrix.

Any suggestions on the same ?