Issue: Modifying the device types attributes are not supported independently in the Subscriber Channel.
Workaround: You can modify them along with their respective phone number attributes, as shown below:
The wd-HomePrimaryDeviceType attribute can be modified along with wd-HomePrimaryPhone attribute.
Similarly, the wd-WorkPrimaryDeviceType can be modified along with wd-WorkPrimaryPhone.
For more information to configure the phone contact attributes, see Configuring Phone Contact Information in Subscriber Channel