Werner Weicht has released uIEC_Man, a GEOS utility that supports mounting and unmounting different disk images while in GEOS. The utility works with GEOS, Wheels, and Megapatch V3. As Werner notes, users are highly encouraged to read the included manual before starting the utility.
One of the most often requested features for uIEC is GEOS support. Given that uIEC emulates a Commodore Disk Drive at the protocol level, not at the hardware level, such support is harder than it sounds. Like many applications of the day, GEOS uses a custom disk drive transfer routine (commonly called a “speeder” or “fastloader”) called diskTurbo to make drive access times more manageable. Since the normal protocol is discarded in favor of a faster variant, successful emulation requires emulating the custom protocol. uIEC uses the sd2iec firmware, which has supported a handful of custom protocols for some time (including JiffyDOS), but does not currently support the GEOS custom protocol.
That may soon change, though. RedumLOA has created a site called “Commodore Bounty” that will allow interested individuals to fund project activities. The first bounty is for sd2iec GEOS support, which has been funded to over $750.00 at the time of this posting. If you are interested in seeing GEOS support on sd2iec and uIEC, please consider a donation.