To the best of my knowledge, brickbug affects only stock ICS 4.0.4. You are ok to flash a custom kernel to root (and get rid of the brickbug issue) as long as you DON'T wipe data BEFORE the flash.
The brickbug is activated by an erase command (emmc cap erase) that is found in the Samsung distributed firmware. This erase command has been removed from custom software so that it won't trigger the brickbug......
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