while your device might default to all trunk.. I am at a loss to why, this is bad choice on their part if you ask me. There is no reason for those ports to be in trunk unless they are going to care more than 1 vlan.
Understanding Access and Trunk Interfaces
Ethernet interfaces can be configured either as access ports or a trunk ports, as follows:
An access port can have only one VLAN configured on the interface; it can carry traffic for only one VLAN.
A trunk port can have two or more VLANs configured on the interface; it can carry traffic for several VLANs simultaneously.
From cisco page
http://www.cisco.com/c/en/us/td/docs/switches/datacenter/nexus5000/sw/configuration/guide/cli/CLIConfigurationGuide/AccessTrunk.html
what I would do with your default setup is change all the ports to ACCESS.. Unless your going to have other switches connected to it, AP with vlans or to a router with vlans on a physical interface ports should be in access mode. Trunk ports are for 1 going to take longer to come up. There is zero point to leaving your ports in trunk unless they need to carry tagged traffic.
Its possible the ports default to auto mode and try to determine what they should be, if they have issue figuring that out they might default to trunk mode. I would have to dig deeper into why your ports are all trunk after a factory reset.
https://supportforums.cisco.com/discussion/12476171/switch-port-modes
Lets be clear your ports should ALL be access, Unless your going to link to another switch or AP or to a port on a router that will have multiple vlans on it.
We could also debate the use of the default vlan 1. In an enterprise/security setup this is normally a big no no. You would set different vlan other than 1 to use for management and all ports would be moved to a holding vlan other than 1 until they need to be placed in the vlan they will be used for. This is to keep mistakes from happening since switches all come up with default vlan 1, so if you do not turn off all your ports they would all be in the default vlan - so in this scenario it would be possible that someone might connect and be on a network you don't wan them in and be able to access resources your management of your infrastructure, etc..
In a HOME setup to me this just adds complexity for no reason. I don't see a problem with just leaving your main lan and even management of your devices all in your default lan, which would be vlan 1. But just be warned that from a pure security standpoint its bad practice to do that. You might get suggestions to change your management vlan, and don't use vlan 1. This way if you forget to configure a port or something worse case someone connects they are connected to nothing else, etc.
Good security practice is also to disable all ports that are not in use.. Ie admin down them until such time they are need. But we are talking a HOME network.. Which just adds more work when you want to plug something in ;) Which is prob not something you want to do. I would suggest you put all your ports into the vlan your going to use most often when you plug in a new device. The will most likely be your lan and its ok to leave that as just default vlan 1. Unless your worried about people coming into your home and plugging stuff in and being on your lan? ;)
