When updating jail without boot and/or kernel eg. /boot and/or /boot/kernel freebsd-update blows up in two ways: +1 It becomes impossible to update jail with freebsd-update from within jail because freebsd-update cannot find kernel files and learn kernel version from them (unless jail is package/world builder that requires kernel files to be present to build something, kernel files in jail make no sense, after all). +2 It breaks up jail update from host, when using freebsd-update basedir -b option. This happens despite jail's ${jailpath}/etc/freebsd-update.conf containing only: 01 # Components of the base system which should be kept updated. 02 Components world Eg. no source or kernel. Tangentially related bug #223470. Case 1 is not easily solvable (without copying some kind of backup of kernel tre back and forth), but case 2 can be hacked around. In case 2, during first install phase mtree fails with: >>Installing updates...mtree: ${jailpath}/boot/kernel: No such file or directory >>cd: ${jailpath}/boot/kernel: No such file or directory >>ln: ${jailpath}/boot/loader: No such file or directory >>ln: ${jailpath}/boot/loader.efi: No such file or directory >>ln: ${jailpath}/boot/userboot.so: No such file or directory >>chflags: ${jailpath}/boot/loader_lua.efi: No such file or directory >>chflags: ${jailpath}/boot/loader_lua: No such file or directory >>chflags: ${jailpath}/boot/userboot_lua.so: No such file or directory This can be hacked around temporarily with: sudo mkdir ${jailpath}/boot/kernel sudo touch ${jailpath}/boot/loader sudo touch ${jailpath}/boot/loader.efi sudo touch ${jailpath}/boot/userboot.so sudo touch ${jailpath}/boot/loader_lua.efi sudo touch ${jailpath}/boot/loader_lua sudo touch ${jailpath}/boot/userboot_lua.so Which will make install move forward. Further phases also have problems with ${jailpath}/rescue missing, but that won't make freebsd-update fail and thus prevent it from updating the jail. I don't know how much life freebs-update has left, given packaged base, but even then it would be cool, if both freebs-update and pkg took into account slimmed down jails without directories like: /boot /boot/kernel /rescue /proc /media /mnt Eg. "even if it doesn't exist, don't try to update it" (unless told explicitly somehow).