Follow the serial flashing guide.
WX5600 <> EX5601 though ?
Yeah they're not same but so similar.
Anyway my question was related to Odido firmware locks.
I solved by booting using mtkuartboot, dumped mtd1 (uboot-env) and there was a "supervisor" password which worked to enter ZLoader.
"sys atck" is not working anymore on b13.
Anyway created the WX5600-T0 device page and added the procedure to extract the supervisor (root) password and entire procedure to flash the device.