No home entry in oraInventory

Today I hit the following scenario - no agent home entry in oraInventory, while I require it when running a script for checking the db installation quality. Due to this the script reported errors in several points, while it should not.
The solution is quite strightforward. In the agent home under AGENT_HOME/oui/bin there is a script attachHome.sh.

#!/bin/sh
OHOME=
OHOMENAME=agent12c1
CUR_DIR=`pwd`
cd $OHOME/oui/bin
./runInstaller -detachhome ORACLE_HOME=$OHOME ORACLE_HOME_NAME=$OHOMENAME $* > /dev/null 2>&1
./runInstaller -attachhome ORACLE_HOME=$OHOME ORACLE_HOME_NAME=$OHOMENAME $* 
cd $CUR_DIR

The script in fact reattaches the home and after the call my script worked properly again.