Windows NT 4.0 was released in 29th July 1996 for following architectures:
The last two, hovewer, were dropped after Service Pack 2 (PowerPC, released in 19th December 1996) and Service Pack 1 (MIPS, released in 12th October 1996), less than half a year after the original release. In result, the application library for these versions is very limited and you often will want to use programs written for Windows 3.1 as all versions of Windows NT 4.0 contain NTVDM emulating 16-bit processor.
Why would you install Windows NT 4.0 on MIPS, then? Except for the fun factor, I don't see many use cases… so why not?
First, we need to make a hard drive image. For that, you can use the following command:
qemu-img create -f qcow2 nt4.img 2G
Where nt4.img is your filename and 2G is the disk size, you can replace G with M for megabytes (keep in mind FAT16 supports only 2 GB partitions and that you can't install Windows NT 4.0 on MIPS with NTFS filesystem).
After that, we're ready to go. Start the machine using the following command:
qemu-system-mips64el -M magnum -net nic,macaddr=12-34-56-78-9A-BC -net user -hda nt4.img -cdrom win_nt_4_iso.iso -global ds1225y.filename=nvram -global ds1225y.size=16384
You should see an error about NVRAM, which occurs everytime unless you make an nvram file. Just skip it, choose Run setup, Initialize system.
You need to run four Actions here:
Now, choose Return to main menu, Exit and most of the time, the system will crash saying:
Testing Interrupt Controller...Error. Self-test failed.
Making you force to reset the QEMU process. It passes around 10% of the time, so you'll get used to setting the clock over and over again. Without NVRAM, you'd need to select all settings each time.
Now, it's time to partition your disk. Choose Run a program and type:
Then, create a partition and exit. Now run:
The installer is exactly the same as in standard Windows NT 4.0.
After it reboots (it probably crash, so you'll need to reset QEMU again), you'll notice new action called "Start Windows NT Workstation Version 4.00," so choose it and install Windows. One more reboot (and probably crash) and the Windows is installed.
What can be installed? Not much. I linked before a file from https://archive.org/download/ntrisc/mips/ and unless you want to compile yourself (why not!), you'll be stuck with that. What have I run?
I suggest downloading Total Commander for Windows 3.1, as it supports FTP and some file archive formats, making your MIPS experience much easier.