Duplicate boot partitions is handled badly

If you have an u-boot device and an pmos install on both an SD card and eMMC then it will load the kernel and initramfs from the storage device the u-boot script was loaded from (which is correct) but then the pmos initramfs will use findfs to locate the initramfs-extra.

If two partitions with a pmOS_boot label exist then the initramfs will use the last one that was probed by the kernel, this is because findfs gets label info from udev symlinks, and in the duplicate label case the symlink in /dev/disk/by-label will get overwritten. the initramfs-extra from another pmos install might contain kernel modules for another kernel version, preventing boot. If you're lucky enough that initramfs-extra works then it will load the wrong rootfs because it uses the same logic.

I don't really see a nice way to handle this, u-boot can pass the correct /dev/mmc* name to the kernel in the cmdline so that all things that are loaded are from the same install, but you can't convince findfs to only check for labels on that block device, it would require a bigger partition detection rewrite.