i followed instructions as per documentation. shorted emmc clock out to ground at power on. unit went into maskrom mode, flashed rk356x_spl_loader and rock-3a-ubuntu-focal offical image using RKDevTool (v2.81 mentioning just in case if there is an issue with this specific version of rkdevtool).
I have serial/ttl access to the unit and seeing the device staying still at this point:
i was using a 12vdc 0.5a adapter but changed it to a 12vdc 2.5a adapter with no change to the situation. Would appreciate some input on what else i can try to help remedy this issue.