I actually just got the 7100i OS (handheld software version 4.1.0.376) using the method above. The OS can be downloaded from Sprint/Nextel right here (
https://www.blackberry.com/SoftwareD...ent=biTZdMddN). It seems to me that the compatibility level of the software has more to do with the design of the handset than anything else (for example, trackwheel vs. track ball, which is one of the reasons why the 8100 OS won't work on an 8700 or a 7100 - in addition, camera vs. no camera seems to have something to do with it as well), so in this instance, you can get it running on the 8700c, even though it's a 7100-model OS.