On: Rufus: Reliable USB Formatting Utility

[numlock86]

same tools really ... stuff like syslinux is included, and for "flashing" you could just use dd.

[wodny → numlock86]

And it's also worth noting that eg. Debian has been providing hybrid images for years. Hybrid meaning you can write them directly to block device like USB drive or burn on CD. They exploit the fact that ISO images have first blocks empty and unused so you can put a classic MBR boot loader there.