A few weeks ago, I finally upgraded my iPhone to firwmare 2.2.1. It was actually an utterly painless operation, thanks to the amazing toolchain.sh by the guys from iphonedevlinux.
I remember in the 1.1.4 days, I had a hard time extracting the MacOS 10.5 SDK on Linux and compiling the openSDK on my Core2 Quad by following saurik's great instructions.
It turns out that building an open SDK for firmware 2.2.1 is actually very simple: getting a copy of the phone's sysroot, building GCC, importing headers from the official iphone SDK, classdumping private frameworks... all these operations are now almost automatic thanks to toolchain.sh.
The icing on the cake: those smart people from iphonedevlinux are friendly and reactive! Another good reason for sending them patches and using their script :)
