mvregress itterations and error definition

Hello, i am trying to estimate a 100X1 vector using 100X2 matrices (B is 2X1 ) B is my coeficient solution.

Howeer there is a problem with regress it converges with a small variation (no matther what large number of samples i give him) 100 ,1000,10000 it converges to a soltion which differs to much from the real number.

So i think the problem is with the number of itterations and the allowed ammont of error.

I have read mvregress document but i cant see there the options to define itterations and error amount.

Could it be done somehow?

Thanks