I managed to get Sierra full working with iMessage etc and Windows 10 in dual boot with uefi on my E6220 but I have a weird problem.
when I let clover inject the kext pc don't boots in OS X in uefi mode but when I install the kext from legacy Sierra bootpack in the right folder (s/l/e and l/e) without that clover inject the kext it boots perfect. is there a method for get the kext injected in uefi mode so that the system stays more vanilla and untouched?
and before someone says clover uefi mode don't works on the E6220 is not true and I can make a picture of the bios where it is in uefi mode and clover string is showed. the trick for get it showing was boot OS X installer format hdd, reboot and install windows in uefi mode and then install OS X and install clover. so is how I got clover selected in the uefi mode.