BCB, BootCnt, and the bootdata partition
Maybe some of you guys have figured this out already but it's probably important to note for people developing custom recovery or boot ROMs.
There is a partition on the internal flash named "bootdata" that stores a files named BCB and BootCnt. The secure bootloader updates BootCnt on every non-sdcard boot and if it gets too high it will automatically boot into the recovery partition instead of the boot partition. So, if you're making any custom ROM to be run from the internal flash then you'll want to reset that file in a boot script somewhere. The shell command "dd if=/dev/zero of=/bootdata/BootCnt bs=1 count=4" would do it (Assuming you've mounted the bootdata partition
The BCB file is similar in that if the secure bootloader boots into the recovery partition for any
reason, it will write to that file and will always boot into the recovery partition until that file is cleared. The shell command to clear that file is "dd if=/dev/zero of=/bootdata/BCB bs=1 count=1088"
The bootdata partition just contains a standard vfat filesystem so you just mount it normally.
And for the love of your god do not delete those files! If you do then booting from internal memory will continue to boot into the recovery partition until they are replaced. You would be able to boot from an SD card to replace them though.