bootadm install-bootloader -R option behaviour is confusing
When invoked with the -R option bootadm install-bootloader will install the loader files onto the specified altroot and then write loader to the MBR of the pool the system is currently booted from – which may not be the same pool. While this behaviour is described in the man page it is confusing and has caught me off guard a few times. What makes this particularly confusing is that the -R option must point to a valid boot environment – it can't just point to just any directory.
There are two ways this could be improved. The first would be to make the -R option check to see if the specified boot environment resides on a different pool from the one that is booted and exit with an error unless the -P option is also specified. The second would be to change the behaviour of the -R option so it updates the MBR of the pool where the boot environment resides instead of the pool which is currently booted. I'd be happy with either one.