Talk:IMG3 File Format
I don't think every iPhone/iPod touch has an ECID -- Isn't it only a 3GS thing? Iemit737 06:01, 27 July 2009 (UTC)
Put your iPhone or iPod Touch in Recovery Mode and look at the USB section in the System Profiler (if you're on Mac), then click on the "Apple Mobile Device...'. In the detalis section (below the devices list) you will see a lot of IDs (also incl. the ECID).
But, it's very good question! I think that in spite of the fact that ECID is present on all devices, only on 3GS it is sigchecked on the bootrom. rusmac