@n1000 It doesn't disable any USB devices (like keyboard and trackpad); my model doesn't have TouchID sensor, but it's likely just another USB peripheral.

This makes sense; the router that gave the IOS device its DHCP service, if it doesn't hear from the device, can reassign that same address. So, it's going into the router settings, not the phone.

Not all partition types and filesystems are bootable for MacOS on your machine (the firmware might matter). The install disk won't repartition or format your HD unless you manually select (from the startup/install disk) menu item disk utility. The installer won't install on a non-bootable type of filesystem.

It depends on model; many models will work faster if identical pairs are used, but will recognize and use unpaired memory. If you install and do the steps above, it'll show you what memory is recognized and working.