Procd: respawn chrooted process?

Any idea how to make procd respawn work with this command?:

procd_set_param command /usr/sbin/chroot /mnt/usb/arch /usr/local/bin/xmppcd

Tried this?

    procd_open_instance
	procd_set_param command /usr/sbin/chroot /mnt/usb/arch /usr/local/bin/xmppcd
	procd_set_param respawn
	procd_close_instance

yes of course. problem is, the process gets respawned multiple times...
my guess is the problem is procd works with chroot's PID...

That was my assumption, and your result. A little more info in your OP would have helped.

See:

That describes OpenWrts jail implementation. But it's of no use for my problem right? Or can i point ujail to the chroot directory?

edit: just found https://openwrt.org/docs/guide-user/services/chroot. unfortunately it doesn't use procd