Topcon GRS-1 Loading GEOID12B

I have an old Topcon GRS-1 and need to update the Geoid to GEOID12B (currently have Geoid12A). I downloaded 12B from the NGS site. I open Survey Link and go to convert file formats. I select geoid *.BIN in the "from" and *.GFF on the "to". When I press convert, a box opens and wants me to select a file with Geoid Canadian95 Passport file *.slv.?ÿThis is not even a step in the manual and makes no sense. I am assuming Survey Link is too old to deal with Geoid12B. Anyone have an answer to this?

Thank you.