uSD (mmc0) not active when eMMC (mmc1) being used

Lots of folks running into the same thing in various thread titles. If the SD card is not inserted at boot up then it will not ever be seen later on by a running device. If it is in place but is not formatted correctly then it will hang the boot process as the boot loader dies if it looks at the SD card and finds no boot files. If it does find boot files there has to be a uEnv.txt file that is correctly setup or I THINK it will boot from the SD card no matter what.

Really, I’m still completely confused on the boot-up situation with the button but right now using a card for extra space seems require some futzing. I have opted to forgo eMMC completely and just boot from an SD card instead. To do that I boot from the SD card and once into the OS I mount the 1st partition of the eMMC and delete the files it contains. From then on it will always boot to my SD card which is 8G or 32G. Plenty of space.

I have found that by the time I download and install my common tools needed I’m out of breathing room on the eMMC anyway.


In this scenario, where you boot from mSD but have a “cleared up” eMMC, can the eMMC still be used ?
Read somewhere that SD’s in general are error-prone over a period, after numerous writes. If that is the case, can run-time generated data (like in a MySQL database) be written to the eMMC and shipped off from there on a periodic basis…


is there a fix?

I found out this is caused by uboot passing the boot arguments to kernel with rootfs=/dev/mmcblk0, while sd is inserted, the emmc actually became /dev/mmcblk1, therefore kernel unable to find rootfs.