is jolla 1 able to boot from emmc

i followed the manual, and i was able to unlock the bootloader, i was able to boot postmarketos from sdcard, but only by issuing a boot command when the phone is connected to the computer, with fastboot.

i didn't understand from the linked wiki article, is it possible to boot jolla without fastboot, without having to connect it to computer?

and is that a same question as - will it boot from emmc? or even from emmc it should be booted by using computer?

thank you.