This did not work for me, sadly. And I JUST finally got around to beating the first game again to get myself into Deadfire; just a few days too late it seems, haha.
This fix did allow me to see the game's save file within Deadfire, which before showed only "No saved games to import", but the now accessible import file had an image that was whited out, and pressing Select didn't function properly. It would click--the UI visually registered it--and make a sound, yet had no effect otherwise; I could hit Select on my save file, but it wouldn't then make the Import button useable. Close, but no cigar,
My PoE 1 version beta is not set to legacy or anything.
Not sure what's different in my situation compared to others who've had success. My savegames are located in the usual User>SaveGames folder, and both my games are on the same drive, and are up to date.
A shame this patch for a nine-year-old game managed to break something the moment I was ready to play Deadfire.