Adding an extra USB 3.1 port to a router (WG1608 - ZBT)

[littleboot]

Introduction:
Hello all, I just finished adding a USB 3.1 port to a router. I think it might be useful for someone else so I will share it here .

Background:
I recently purchased a "WG1608 - ZBT" router from AliExpress with the goal of using it a IOT hub device.
I started this project because I was looking for an alternative to running my HomeAssistant instance inside a VM on my main PC.
At first I looked into the Raspberry Pi for this because it is recommended by HomeAssistant, but when I added everything together it was rather expensive: rp4-8gb + housing + adapter + sd card = ~€130 and in addition out of stock.
So I went on AliExpress to look for an alternative and purchased a Chuwi herobox (more info below) a low power passively cooled mini PC for around ~€180 inc. shipping for use as low power server instead of the pi.
This setup worked great and I moved on to my next project an newifi-d3 routter that runs OpenWrt, I attached a powered USB-hub and a external USB-SSD to it and configured it all as a samba file server so I  have access to a network folder when connected to this network.
In addition I installed the RNDIS USB-tethering driver so I can connect my phone to the router to get internet  access on this network.
This setup works great (I use it every day) but it doesn't look very nice with the external usb-hub and SSD attached to the router with zip-ties. I would rather have a router with multiple USB 3.1 ports so I don't need an additional external USB-hub.
So I went on AliExpress again to look for a solution and I found the WG1608 - ZBT router.
This router was quite affordable, powerful and runs openWrt and has a lot of features and two internal expansion slots (mini PCIE and M.2) that are intended to be used with GSM modules.
This got me thinking, I do not need the GSM module but maybe I can use the expansion slots for something else. I looked up how these modules communicate and it turned out to be USB (After I damaged a M.2 SSD and mPCEI SSD and testing what would happen  The voltage on the +3.3V pins of the mPCIE standard is 4.1V in this router).
I ordered the router and when I received it I took it apart to inspect the circuit as it turned out the router has a internal 4-port USB3.1 hub based around the GL3510 - GYNESYS IC that is connected to the MT7621 host CPU using an USB3.1 interface. The downstream ports of this internal USB-hub that are routed are connected to:
-Front USB port (USB2.0 + 3.1 from the internal hub)
-Internal mini PCIE expansion slot (USB3.1 from the internal hub) (USB2.0 directly connected to MT7621 host CPU)
-Internal M.2 expansion slot (USB2.0 + 3.1 from the internal hub)

I leaned that an USB3.1 port consists of 2 separate USB interfaces 1x USB2.0 + 1x USB3.1 neat .
I'm was thinking of designing a custom board to breakout all USB interfaces to 4 separate USB connectors but I went on AliExpress again and solved my problem another way.
I ordered a "Mini PCI-E To USB3.0 Expansion board" for ~€7. When I received it I was a bit disappointing because it was actually a "Mini PCI-E To USB2.0 Expansion board" and I set out to fix this.
I fixed it by soldering the missing USB3.1 connections to the correct pads of the mPCIE card edge connector.

Result:

see topic attachement project notes pdf document.
I tested and verified that I was able to use the newly added internal USB2.0/3.1 port of the router (both 2.0 and 3.1 USB is working).
Because I'm now using the front SD-card slot of the router to expand the storage I actually do not need to use the new USB port for storage.
I might use this USB port to add an USB to zigbee adapter, LoRa concentrator or bluetooth adapter so the router is able to connect to other network types, but at the moment I'm busy with in getting HomeAssistant installed again on the device.

Conclusion:
Most problems in life can be solved using AliExpress for others you'll need a soldering iron.

Links:
Mini PCI-E To USB3.0 Expansion board (actually USB 2.0)
https://www.aliexpress.com/item/4001229499037.html ~€7,-

CHUWI Herobox
Mini Desktop PC Intel Celeron J4125, 2.0GHz up to 2.7GHz Quad Core 64 bit, Windows10 OS, 8GB RAM 256GB SSD, BT 4.0 and Dual WiFi, Mini HD, Type-C
https://www.aliexpress.com/item/1005003258074855.html ~€180,-

WG1608 - ZBT
Dual band WiFi router, 1x WAN, 4x LAN, 1x USB 3.0, 1x SIM, 1x microSDXC, 1x M-PCIE, 1x M.2
https://www.aliexpress.com/item/1005004265119598.html ~€90 (32MB 512MB PCIE version)

mini PCIE pinout
https://pinoutguide.com/Slots/mini_pcie_pinout.shtml

HomeAssistant on OpenWrt installation script
As of writing this script does not work anymore, I have used it and it did work on my hardware sadly I did not make a backup. I'm currently looking into this or solving it using a docker container for the router CPU architecture.
https://github.com/openlumi/homeassistant_on_openwrt