The one included in KR_KT ROM is also included in official 2.2.1, so there is no "stock" and "non-stock" anymore. They're both stock.
One difference I know of is that the newer bootloader enlarges or otherwise takes care of BOOT partition where boot.img is stored, and allows people with bad sector in that partition flashing larger boot.img than the older one.
Google Glass, which recently received its official update … more
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