excel - Fill certain cells with value above them -

excel - Fill certain cells with value above them -

i have info range transform this:

before: after: po001808 |po001808 po001808 |po001808 false |po001808 false |po001808 false |po001808 po001845 |po001845 po001845 |po001845 po001845 |po001845 false |po001845 false |po001845

i trying fill cells have false, value above them, repeat process when new value reached. have utilize vba formula or possible simple functions?

in after column, cell b2:

=if($a2=false,$b1,$a2)

and drag down.

excel vba cell