Multi-Boot is something that is meant for you if you love trying out different ROMs on your device. New ROMs are great but it is difficult to interpret its functionality on your device by just having a look at the ROM’s thread. You need to try it yourself and Multi-boot lets you boot into a secondary ROM that boots from your device’s SD card or internal storage.
Multi-boot helps you keep your current stable ROM and try out the other ROM (secondary ROM) using the zip file you place in your device’s internal or external storage.
Multi-boot feature is now available on Sony Xperia U, Sola and Go. thanks to XDA Recognized Developer munjeni‘s app Multi Boot Manager. The Multi Boot Manager app uses kexec feature in a kernel to multi-boot into a different ROM other than the primary ROM. So make sure any ROM you use is kexec enabled. If not, it is recommended not to try this feature as it would not boot.