MiWiFi 4
Xiaomi MiWiFi 4

Thumbnail for the Xiaomi MiWiFi 4 router with Gigabit WiFi, 2 N/A ETH-ports and
0 USB-ports

The Xiaomi MiWiFi 4 router has Gigabit WiFi, 2 N/A ETH-ports and 0 USB-ports.
It is also known as the Xiaomi Xiaomi MiWiFi 4.It also supports custom firmwares like: OpenWrt, LEDE Project

Quick links:
Default password/Login
Flashing Custom Firmwares

MiWiFi 4 router specifications (specs)

System specs
CPU: 880 MHz
RAM: 128 MiB
Flash: 128 MiB
Custom firmwares: OpenWrt, LEDE Project

Connectivity
WiFi: Gigabit (abgn+ac)
WiFi bands: n/a
WiFi throughput: n/a
WAN: 1 x N/A port
ETH: 2 x N/A ports
USB-ports: 0

Hard reset instructions for Xiaomi MiWiFi 4

If your MiWiFi 4 router is not working as it should, dropping connections or not being responsive, you should first do a reset of the router to see if the problems persist. Other scenarios where you might want to reset your router is if you've forgotten the password or misconfigured it and can't get access anymore.
Your can reset your Xiaomi MiWiFi 4 in the following way(s):

The 30-30-30 reset

There are no specific instructions for this model yet, but you can always do the 30-30-30 reset as follows:

When router is powered on, press the reset button and hold for 30 seconds. (Use a paper clip or something sharp)
While holding the reset button pressed, unplug the power of the router and hold the reset button for 30 seconds
While still holding the reset button down, turn on the power to the unit again and hold for another 30 seconds.

This process usually works for resetting any router to it's factory setting.

Note: It is worth reading more about how to reset routers with the 30 30 30 reset and what the risks and considerations are when resetting your router this way, instead of just rebooting it.

Default factory settings for Xiaomi MiWiFi 4

If you have performed a reset of your MiWiFi 4 device or not changed the defaults, you should be able to access it with the following settings:

Default Network name (SSID): Xiaomi_XYXYXYX,Xiaomi_XYXYXYX_5G
Default Gateway IP: 192.168.31.1 Xiaomi login instructions
Default subnet mask: 255.255.255.0
Default DNS server: 192.168.31.1
Note: If you are using the default settings you should change them to increase security and prevent unathorized access to your network.

MiWiFi 4 Firmwares

Staying up to date with the latest firmware is a good idea to keep your router even more secure from various security flaws.
If you want to squeeze a little bit of extra functionality out of your router, consider flashing an open-source firmware like dd-wrt, openWRT or LEDE. Flashing a custom ROM can greatly increase the stability and functionality of your old router.
Following are the firmwares that we have identified existing for the Xiaomi MiWiFi 4:

Flashing OpenWrt on the Xiaomi MiWiFi 4

The Xiaomi MiWiFi 4 is supported by OpenWrt according to their Table of Hardware. So flashing OpenWrt onto it should be quite straigthforward.
We couldn't find any specific instructions for flashin OpenWrt on the Xiaomi MiWiFi 4, but since it's listed in their Table of Hardware as supported, you can head over to the OpenWrt install instructions and read on there.
Note: Flashing custom firmwares is always on you're on own risk. Make sure to read OpenWrt's wikis to understand the risks and how to proceed if something goes wrong.

Flashing LEDE Project on the MiWiFi 4

The Xiaomi MiWiFi 4 is also supported by the LEDE Project.
To install LEDE aquire the correct firmware from their Firmware downloads page and then follow the instructions on their Quick Start Guide
Note: Make sure to read the LEDE wikis carefully before flashing.