(This is an extension of question \ell in MinionPro, but sadly I can't add comments on S.E. yet.)
Similar to the issue of using \ell in recent versions of MinionPro, which is solved by replacing /afii61289 by /uni2113 in the file base-MinionPro-ab.enc, the symbol \openg (and probably others, too) is not found anymore due to the changed encoding. What does /afii10069.ital have to be replaced by in base-MinionPro-ab.enc?
Is there some way of printing a table of all glyphs in a font to find that information?