Yoou are probably dealing with transactions marked for Box B or Box E.
For non-covered securities ( BOX B or E) showing zero (wrong) basis, enter the correct basis yourself. Use code "B" and put -0- in col (g).
This means you enter the basis from your own records or calculations.
For Box A or D, leave basis as reported, use Code "B" and put an adjustment in col(g). If the basis is not reported to IRS, there's nothing to adjust. - If you check the box indicating you have other boxes on your 1099-B to enter, TurboTax will do it this way.