hikey: README: Update documentation to use boot.img instead of boot_fat.uefi.img

Update the README file to use the boot.img output rather then
the boot_fat.uefi.img

Change-Id: Ice7cc25925c7865d5962c1c5cbbac29ce947a621
Signed-off-by: John Stultz <john.stultz@linaro.org>
diff --git a/README b/README
index 9425f02..b4c97c6 100644
--- a/README
+++ b/README
@@ -30,7 +30,7 @@
 
 * Flashing images:
 Enter fastboot mode by linking J15 1-2 and 5-6 pins
-$ fastboot flash boot out/target/product/hikey/boot_fat.uefi.img
+$ fastboot flash boot out/target/product/hikey/boot.img
 $ fastboot flash system out/target/product/hikey/system.img
 $ fastboot flash cache out/target/product/hikey/cache.img
 $ fastboot flash userdata out/target/product/hikey/userdata.img
@@ -43,10 +43,12 @@
 $ make ARCH=arm64 hikey_defconfig
 $ make ARCH=arm64 CROSS_COMPILE=aarch64-linux-android- -j24
 Output: arch/arm64/boot/Image & arch/arm64/boot/dts/hisilicon/hi6220-hikey.dtb
-   copy Image and hi6220-hikey.dtb to hikey-kernel directory
+   copy Image-dtb and hi6220-hikey.dtb to hikey-kernel directory
 
 * Setting monitor resolution
-Edit device/linaro/hikey/bootloader/EFI/BOOT/grub.cfg
+Add to BOARD_KERNEL_CMDLINE in BoardConfig.mk or
+if you are setting TARGET_BOOTIMAGE_USE_FAT=true edit
+device/linaro/hikey/bootloader/EFI/BOOT/grub.cfg
 Set video= (for example for 24” monitor): video=HDMI-A-1:1280x800@60
 
 * Kernel serial output (uart3):