I played the Pool of Radiance saga (FIRST edition AD&D, not 2E as is commonly claimed) thirty years ago on the Commodore 64, and was looking forward to doing so again, complete with Hillsfar (to gain about 15-20 extra HP per character without cheating).

However, GOG Support is unwilling and unable to help me transfer characters from Pool of Radiance (PoR) into Hillsfar, despite the fact that instructions for the adventure games of the saga (PoR -> CotAB -> SotSB -> PoD) don't work for the single action game in the saga (PoR -> Hillsfar -> CotAB -> SotSB -> PoD).

Finding a 3rd-party post on another site where somebody not using the GOG versions got it to work, I've been able to figure out how to make the GOG versions of POR -> Hillsfar work correctly. These steps are for the PC versions; not being familiar with xNix (Linux/Mac OS10+), I am unable to translate them for those OS.

Step 1: After saving your PoR game, remove from the party any characters that you wish to transfer to Hillsfar..
Step 2: Locate the characters in <Install Drive>:\GOG Games\Pool of Radiance\SAVE as <First 8 Characters of Name>.CHA.
Step 3: Copy these files to <Install Drive>:\GOG Games\Hillsfar\POOLRAD
Step 4: Create <Install Drive>:\GOG Games\Hillsfar\HILLSFAR
Step 5: Open Windows Explorer to <Install Drive>:\GOG Games\Hillsfar, and another instance to <Install Drive>:\GOG Games\Hillsfar\DOSBOX
Step 6: From \Hillsfar, drag COPYHILL.exe to the other Explorer window and drop it onto \DOSBOX\DOSBox.exe
Step 7: From the COPYHILL menu, transfer "Pool of Radiance to Hillsfar", accepting the default directories and exit the utility.
Step 8: Copy the resulting files up one directory level, from <Install Drive>:\GOG Games\Hillsfar\HILLSFAR to <Install Drive>:\GOG Games\Hillsfar.
Step 9: Launch Hillsfar
Step 10: Once you get to the menu, select "Transfer a Chacter", followed by "From Pool of Radiance". Your character(s) will now be available for use in Hillsfar.

I have not yet attempted to combine POR and Hillsfar characters for conversion into Curse of the Azure Bonds (CotAB). With the difficulty I've had in getting POR -> Hillsfar done, I'm ready to just use the Gold Box Companion editors to update characters after a direct conversion from POR. (If you want a 'proper' transfer from Hillsfar -> CotAB, let GOG Support do their job and figure it out for us.)