Booting Linux is easy - everyone does it, every day. But there are challenges around: On devices with a display, everyone wants to have a flicker-free boot process, with a shiny penguin splash screen. And of course, booting shall be possible from every boot medium around, be it NAND flash, an SD card, a serial line or from USB with the DFU protocol. Last but not least, things have not only to be fast, but really fast.

Following an introduction to the Barebox bootloader (formerly known as U-Boot-v2) and its features, we outline how this bootloader can be used to achieve quickboot requirements. We demonstrate how to boot a 400 MHz MX27 ARM device into a fully operational graphical Qt application plus standard userspace services in < 6 s. And in case that the audience doesn't qualify that as really fast, we boot an MX35 into the userspace in 336 ms.