how to make a bootable USB linux sine pinebook will not boot up

[River]

The answer to both questions is "no".

But if you can't boot, you won't be able to boot to USB, either.

You will need to re-flash your eMMC. Or disable or remove it and boot from micro-SD.  But flashing the eMMC is the way to go.  The easiest way is with an eMMC to USB adaptor; and by flashing the eMMC from a different computer. 

You can reflash the eMMC from the PBP, but it's tricky.

If you have written to the SPI flash ROM, all the above is moot.

 I have not written SPI flash rom.
I will look into buying an adapter from Pine Store. 
I was able to Fix   Etcher on my Windows PC so I can make  linux bootable  micro SD card.  I needed to add permissions for Etcher  in the  Folders section of the Settings for Virus & threat protection.

Could you  tell me how exactly the Switch on bottom works?  
Does switching it one way make it only boot to SD card and switch other way only boots to EMMC? 

what does the reset button do ?  and what sequence do you press it, with emmc out or when it's installed?