Just be careful in case of ENG 2 damage and/or fire, if you have discharged the bottles and you plan on using the APU bleed for the overweight landing, you should shut off the crossbleed, otherwise after a few seconds also the pack 2 will be fed by the APU, resulting in contamination.
In case of same situation on ENG 1, just forget APU bleed and go packs off. APU bleed first would feed pack 1, which you clearly don't want in this case, then after a few seconds automatically the pack 2 through the cross bleed valve.