Just a note I want to add, I read through the pages- if you want to go from ICS to CM7, I'm pretty sure you have to flash stock, re-root and flash CM7 from stock 2.3.6. Otherwise it won't boot and you'll get a bootloop.
Although maybe ICS allows you to do that? I've only done CM9 -> stock restore, so I don't know how well CM9 -> CM7 works.
On the safe side, flash stock 2.3.6, root and flash CM7 from there. Although as pryerleee suggested try going straight from ICS to CM7. It might work...
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