Default jtag or serial console for bootloader

Anyone know if this board has jtag or serial console pins anywhere, to debug a bootloader problem?

Or any other way to debug a bootloader problem when you specifically need to debug a 4.3 bootloader to see why it's not booting a new recovery? (twrp built from 4.4-omni)

Using the 4.4 engineering bootloader is not applicable because 4.4 bootloaders boot the new recovery fine, no problem to fix.

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