RE jump to FEL on BROM step 2 failure: I'm not sure the boot process description is exactly right. I think it only jumps to FEL if it fails all three boot attemps (SD slot 0, nand, SD slot 2)

This does not describe the boot-to-recovery process in U-Boot mode (ICS-style). In this mode the linux.ini file has a single entry that provides information to chainload u-boot.bin. Since the boot-to-recovery key combination is detected by boot.axf, how is this passed to U-Boot which knows how to boot in normal and recovery modes?