There is no setting. Xerox does not allow 3rd party toner in their machines. Most desktop printers(such as the 6027) are sold at a loss with the hope that cost is recovered in the consumables.
It's on the 3rd party supplier to make a chip that mimics the OEM (in this case Xerox).
Be aware the machine is shipped with a toner neutral chip. This toner isn't available on the open market and is shipped with new machines from the factory.
The first time you change the toner with an official Xerox brand toner, the chip on the new toner programs the machine to either sold(version depends on region of the world) or metered, and from that point forward it will only accept one variety, not the other (It also won't accept neutral again either).
3rd party toner supliers typically don't mimic metered, as the customer gets those for free
If they mimiced nuetral, they can only supply toner to machines who have never switched out their toner with an official toner.
If they mimiced sold. Hopefully they copied the version intended for the country your from, and you just were supplied a defective chip, and the next will work. Though be warned, there are threads on this forum from customers who have turned their machine into a paperweight going with 3rd party.
