I understand. eMMC can be erased. But I'm talking about the effect. After turning on, tvbox is loaded with sdcard and then if you give the reboot command, the disk connected via USB3 is loaded.
Maybe this can be used somehow to create a boot with USB3?
I install armbian to eMMC, SDCard and External SSD on USB3.
After power on - os loaded from SDCard, if I reboot, loaded from SSD USB3.
If disable power, os loaded from sdcard.
How make sdcard for load from SSD USB3?
Thanks.