Roy rm77

Installing ChromeOS Flex (hardware accelerated) on QEMU for Windows

A word of warning. This will be slow and buggy. Do not attempt to use this as a daily driver.

Requirements:

Windows 10 or 11 (x64)

Download Files:

Download QEMU
Download ChromeOS Flex (remember to download the file; do NOT use Chromebook Recovery Utility)

About

I faced bandwidth issues between a WG Peer and a WG server. Download bandwidth when downloading from WG Server to WG peer was reduced significantly and upload bandwidth was practically non existent.
I found a few reddit posts that said that we need to choose the right MTU. So I wrote a script to find an optimal MTU.
Ideally I would have liked to have run all possible MTU configurations for both WG Server and WG Peer but for simplicity I choose to fix the WG Server to the original 1420 MTU and tried all MTUs from 1280 to 1500 for the WG Peer.

Testing

On WG server, I started an iperf3 server
On WG peer, I wrote a script that does the following:
- wg-quick down wg0
Edit MTU in the /etc/wireguard/wg0.conf file

Install Alpine Linux Via Minirootfs Archive.

Prerequisites.

Any live usb bootable.
Alpine Linux minirootfs archive, we can get it here. We can choose alpine-minirootfs-3.20.2-x86_64.tar.gz.
Some partitions, for root system (/), efi (if you have uefi machine) and swap (optional).
Basic commandline knowledge.

Steps.

Ubuntu 24.04 Firefox snap replacement

I need a proper Firefox installation and not the snap version. The snap version does not work properly with Smart Cards. Although it seems to be possible to get it to work with smart cards it is extremely difficult and I don't care to try and make it work. This is not a tutorial on how to get your PIV or CAC to work. Also snaps suck. Canonical will heopfully abandon snaps in the future.

Remove Snap Firefox

sudo snap disable firefox
sudo snap remove --purge firefox
error: cannot perform the following tasks:
- Remove data for snap "firefox" (1943) (unlinkat /var/snap/firefox/common/host-hunspell/en_ZA.dic: read-only file system)

Setting up Qemu with a tap interface

There are two parts to networking within QEMU:

The virtual network device that is provided to the guest (e.g. a PCI network card).
The network backend that interacts with the emulated NIC (e.g. puts packets onto the host's network).

Example: User mode network

Common Options

-#, --progress-bar Make curl display a simple progress bar instead of the more informational standard meter.

-b, --cookie <name=data> Supply cookie with request. If no =, then specifies the cookie file to use (see -c).

-c, --cookie-jar <file name> File to save response cookies to.

An Ubuntu WiFi Secure Captive Portal

Improvements, suggestions & fixes are welcome!

Captive portals can be a pain. Here's an opinionated and no-doubt entirely imperfect guide to setting one up for a WiFi access point on Ubuntu (tested on 20+), utilising Network Manager, DNSMasq, HA Proxy and (optionally) Let's Encrypt for a secure, locally hosted landing page.

_Note: This setup was originally designed for an offline WLAN, providing access to a small number of locally hosted domains ... think the WiFi media portal on a flight or boat. If you are looking to provide internet access behind a captive portal then this guide won't get you all the way there. That said, many routers have this capability built in, as do any number of open source router firmware solutions. So you probably don't need to roll your own. If you'd like to try anyway, Ha Proxy Stick Tables would probably come in handy. Very happy to update the guide with any p

	import paramiko
	k = paramiko.RSAKey.from_private_key_file("/Users/whatever/Downloads/mykey.pem")
	c = paramiko.SSHClient()
	c.set_missing_host_key_policy(paramiko.AutoAddPolicy())
	print "connecting"
	c.connect( hostname = "www.acme.com", username = "ubuntu", pkey = k )
	print "connected"
	commands = [ "/home/ubuntu/firstscript.sh", "/home/ubuntu/secondscript.sh" ]
	for command in commands:
	print "Executing {}".format( command )

	# Script for Ubuntu: Nvidia Multi-GPU Installation and Testing (Adaptable for other distros)

	# Step 0: Clean Nvidia Installation
	# If you need to completely remove a previous Nvidia installation, use these commands.
	# This ensures that you start with a clean slate for a new installation.
	sudo apt-get --purge remove "nvidia"
	sudo apt-get --purge remove "cuda" "cudnn" "cublas" "cufft" "cufile" "curand" "cusolver" "cusparse" "gds-tools" "npp" "nvjpeg" "nsight" "nvvm" "libnccl*"

	# Verify that the removal is complete by checking if any Nvidia, CUDA, or cuDNN packages are still installed.
	apt list --installed \| grep cuda

	#!/bin/busybox sh

	# 1) Download a prebuilt BusyBox binary here:
	# https://busybox.net/downloads/binaries/
	#
	# 2) Prepare your kernel
	# cp /boot/vmlinuz vmlinuz
	#
	# 3) Copy the files
	# install -Dm0755 busybox-x86_64 initramfs/bin/busybox