SD card not always detected
The SD card (sda) seems to only be present when loading u-boot from eMMC and booting from the eMMC stock image. The following scenarios have strange results:
u-boot on eMMC -> Linux over fastboot -> eMMC rootfs: system boots, sda available
u-boot on eMMC -> Linux over fastboot -> SD rootfs: kernel hangs waiting for sda
u-boot on USB -> Linux over fastboot -> eMMC rootfs: system boots, sda unavailable
u-boot on USB -> Linux over fastboot -> SD rootfs: kernel hangs waiting for sda
- 'u-boot on eMMC' means I'm booting from eMMC, interrupted u-boot when booting and ran 'fastboot 0'
- 'u-boot on USB' means I loaded u-boot using uuu
- 'Linux over fastboot' means I loaded the kernel and device tree using uuu
- 'eMMC rootfs' means I set 'root=/dev/mmcblkp2' in bootargs
- 'SD rootfs' means I set 'root=/dev/sda' in bootargs