Boot From Micro SD Instead of Existing Flashed eMMC

I have eMMC flashed with image and a Micro SD with an image. Given the boot order being eMMC > Micro SD > USB . Is there any way to boot from Micro SD without erasing the eMMC img? What are the steps if so?

Tried 3 different usb drives multiple os - my red light is solid and green light remains solid as well. USB drives have indicator light that is never lit. No indication any recognition of the usb is taking place.
My conclusion is the board is defective unless you have alternative explanation.

There is generally no changing the boot order easily. Remove the eMMC.

Which board, which image? There are many.

I havent tried booting from usb, since there is an sd slot meant for the purpose on the potato. I remember reading that the bootloader has to be on a SD or eMMC, not usb.

Did you extract the image before flashing?

Are you sure you your power suply is to spec? You can check the 5V pin and ground with a multimeter. If it’s not between 5-5.5V you got power problems.

@bcy, sorry I forgot the tag, I meant to direct these questions at you.

I knew I saw that somewhere:

Attempting to dual boot came up with a cool solution to make eMMC grub exit and continue booting attempt from uSD instead.