We're not directly involved with the ReactOS project. Nevertheless, it's one of the most important open source projects active today, and we realized that for the project to grow and develop, it had to be easier for end users to install, try out, and use.
The current installer images are mostly designed to be used in virtual machines - VMWare, Parallels, QEMU, VirtualBox, etc. - and not on real computers. On most computers they won't even boot. But the ReactOS team has done great work, and we want to see more installations on real computers. This meant building a version that could be easily run or installed from a USB stick, so we did.
Our installation package will allow you to create bootable USB drives that will boot and install easily on almost any BIOS- or UEFI-firmware based system and that offer the option of running either as a Live OS or a full installer on startup. Memory requirements are a bit higher because the installation runs from a RAM disk in order to avoid compatibity issues with your computer's USB hardware: you'll need at least 512MB of RAM.
Previously we attempted to provide single disk image files that could be written directly. However an unspecified issue seems to have impacted the integrity of these images upon download and none would boot. We therefore created a workaround.
To write the image to a USB stick, you need four downloads. One is a program called RMPrepUSB, which offers a one-click installation of a bootloader called SYSLINUX. Insert your flash drive, format it, use RMPrepUSB to install SYSLINUX to the drive's root directory, and then copy the contents of our ZIP file to the root directory of the drive.
You also need whichever ReactOS images you want to use. Download both the Live and Boot versions, rename the Live image to live.iso and the Boot image to main.iso, then copy them along with our package to the root directory of the flash drive you've just prepared. And you're done!
PLF ReactOS USB Package
Released under the Creative Commons - NonCommercial/NoDerivatives License