I have 2 of them, but I flip the firmware back and forth all the time. You can keep all the firmwares on a spare SD card and just rename them and boot with them as needed. You don't lose anything when you flip them anyway, since the images are stored on SD cards and not the unit itself.
"I appreciate SDF but it's a general-purpose server and the name doesn't make it obvious that it's about art." - Eugen Rochko