-1. Currenly, U-Boot run at the highest exception level processor
- supported and jump to EL2 or optionally EL1 before enter OS.
+1. U-Boot can run at any exception level it is entered in, it is
+ recommened to enter it in EL3 if U-Boot takes some responsibilities of a
+ classical firmware (like initial hardware setup, CPU errata workarounds
+ or SMP bringup). U-Boot can be entered in EL2 when its main purpose is
+ that of a boot loader. It can drop to lower exception levels before
+ entering the OS.