Sorry. My explanation was insufficient.
The file system is built within emmc and the microSD is used as storage for data.
However, when a broken microSD is inserted, it outputs an error like the attached file and will not boot.
When the microSD is removed and power is turned on, it boots up with no problem. Naturally, the pin setting is to boot in emmc mode.
There is one partition in the microSD, which can be formatted. Therefore, I expect that some sectors are abnormal.
I am using tinkerboard to send data to the server. At that time, I also send the status of the tinkerboard as well.
Ultimately, I would like to be able to start the tinkerboard even if the microSD card is damaged, and to be able to tell the server that there is something wrong with the tinkerboard.
Therefore, we would like to be able to boot the OS by emmc boot even if the microSD is damaged.