ASUS Tinker (not S version) - will not boot (MASKROM?)

Hi, new to forum (and Tinker), having this problem:

Tinker board loads image for a while, then stops and while the text on the terminal rushes too fast, I could spot “finished”, and then Tinker closes with all LEDs off.

Per Google, it seems mandatory to insert a jumper to set boot priority, into the MASKROM position. The problem then is that this Tinker did not come with a jumper, nor are there jumper pins soldered on the PCB.

How do I solve this so that Tinker loads from SD Card?

same topic as been opened on GitHub