config EFI bool "Support running U-Boot from EFI" depends on X86 help U-Boot can be started from EFI on certain platforms. This allows EFI to perform most of the system init and then jump to U-Boot for final system boot. Another option is to run U-Boot as an EFI application, with U-Boot using EFI's drivers instead of its own. choice prompt "Select EFI mode to use" depends on X86 && EFI config EFI_APP bool "Support running as an EFI application" help Build U-Boot as an application which can be started from EFI. This is useful for examining a platform in the early stages of porting U-Boot to it. It allows only very basic functionality, such as a command prompt and memory and I/O functions. Use 'reset' to return to EFI. config EFI_STUB bool "Support running as an EFI payload" endchoice config EFI_RAM_SIZE hex "Amount of EFI RAM for U-Boot" depends on EFI_APP default 0x2000000 help Set the amount of EFI RAM which is claimed by U-Boot for its own use. U-Boot allocates this from EFI on start-up (along with a few other smaller amounts) and it can never be increased after that. It is used as the RAM size in with U-Boot. choice prompt "EFI 32/64-bit selection" depends on EFI_STUB help EFI does not support mixing 32-bit and 64-bit modes. This is a significant problem because it means that you must build a stub with the correct type for EFI to load it correctly. If you are using 32-bit EFI, select 32-bit here, else select 64-bit. Failure to do this may produce no error message - it just won't start! config EFI_STUB_32BIT bool "Produce a stub for running with 32-bit EFI" config EFI_STUB_64BIT bool "Produce a stub for running with 64-bit EFI" endchoice