I’ve finally had a chance to look into the recent problems with the Ultima Patcher and they were indeed caused by the new versions of the GOG installers which now use two rather than one Dosbox config file. At the time of writing, all of the Ultima games on GOG are using version 2 installers except Ultima 7/Serpent Isle which will presumably follow shortly. Among other things, the new setup broke every patch that needed to change the Dosbox config which has now been fixed in version 1.5. This new version isn’t compatible with the original GOG releases when it comes to MT-32 emulation so I’ll leave version 1.42 up in case anyone still wants to use it with the older installers.
Other minor fixes include the correct filenames for the MT-32 ROM’s in the description text (underscores instead of dashes), and the patcher now looks in the new default install directories before asking for a game installation directory.