With the restoration of independence, the Portuguese flag remained as it had been before its absorption by Spain in 1580. It also became popular the use of the so-called “restoration flag”, consisting of the Order of Christ Cross on a green background. White and green were the colours of Bragança dynasty, too.
Sources: Anonymous manuscript from 1670, reprinted in Amsterdam 1966 as «Flags of the World 1669-1670» | Wikipedia(pt):Evolução da bandeira de Portugal
Sizes: ensign W12 x L18 mm, mast flags W8 x L12 mm, jack W6 x L9 mm, pennant W4 x L48 mm.