If you want to extend your UC almost for free, you can re-use pcb which comes with non LTE unit.
There are 2 unused usb ports there, which requires some soldering
I decided that i need only one external USB, and internal contacts i will leave for possible internal device mount.
With super glue, USB DIP pcb and strong knife you can cut out and mount usb directly to the board(could be safely cut where mounted, but is something would go wrong - you can solder all contacts, including speakers directly to pci)
I mounted it and re-used small black grill from other dead device to cover up(+bonus cooling)
for an external usb port i would suggest soldering a USBLC6-2SC6 in between, it is not required, but it will protect the main pcb from an electric discharge. you just need to solder one pin to the already existing 5V, the other to GND and then let D+ and D- go thru it.
pretty cheap: 5PCS USBLC6-2SC6 TVS DIODE 5.25VWM 17VC SOT23-6 NEW | eBay
Alternative: directly use a presoldered USB-PCB with it already installed, there are a few available on ebay/aliexpress, at least in europe.
currently cannot tell you exact, as i filled this with glue. but reffer to the first photo and the comment. you could find there dp/dm and +5v/gnd, with multimeter you will easily determine power points, than just try ti connect some device. if not recognized - switch dp/dm pins
About to do this as it’s the last part of my mods and I’m freaking out. I suck so bad at soldering stuff this small. First I need to figure out how to strip these 4 tiny wires so I can even begin. Really hope I don’t botch this…