/etc/ioconfig maps devices to instance numbers.
The ioconfig file is initially created at install time. At boot up, ioinit runs and checks ioconfig consistency with the kernel (initiated by /stand/ioconfig). If it is inconsistent, the box boots into single user mode so a valid /etc/ioconfig can be restored or a new one created using ioinit -c .
If instance numbers need to be re-assigned, rmsf and insfcan be used. Another method (probably not recommended by HP) is to move /etc/ioconfig, boot into single user mode and allocate the instance number to the hardware path using insf.