Register the performance you want to boot up to in a Live Set by pressing Shift + Live Set (if your performance is already in a live set, you don't have to do this step. Just go to the Live Set and select your performance). Then go to Utility, Settings, System. Set Power On Mode to Live Set. Set Initial Live Set to the bank, page, and slot your performance is assigned to. If you were already on that performance before entering the Utility page, you can tap "Set Current Slot".

Now the MODX will boot up in Live Set and have your performance selected.

You can have the instrument Boot up in Performance Mode, or if you wish a specific sound, select to boot up in “LIVE SETl and then tell it which Live Set Bank and Slot. You can choose any Preset, User or Library Live Set Slot.

Press [UTILITY] > “Settings” > “System”
Choose the “Power On Mode” = Live Set
Set the Live Set target as you desire.