Here is the step by step instruction on programming Toyota G chip key by using Superobd SKP900 key programmer.
NOTE: you need initialize your ECU before all key lost.
You need prepare the register main key and new key for use.
Then connect SKP-900 device to the car
The immo lamp on the car falshes
Then start SKP900
Choose OBDII adapter and turn ignition on
Program succeed after immo lamp extinction
Tips: copy G chip by Handy Baby vs. program G key by SKP900:
With JMD handy baby, you need the original key to copy data for the new key via a specialialized G chip
but skp900 key programmer can directly program a key with a G chip in the car.