pico-imx7d: Add "how to boot with NXP 4.1 Kernel"

The NXP 4.1 kernel needs to boot with secure boot.

Add information on how to enable secure boot mode.

Signed-off-by: Vanessa Maegima <vanessa.maegima@nxp.com>

diff --git a/board/technexion/pico-imx7d/README b/board/technexion/pico-imx7d/README
index a2805ee0801ff3816dff08d2ccfd0970e1d5f7b0..8af4effa7890ea82661bcd99d827be524f1356e9 100644 (file)
--- a/board/technexion/pico-imx7d/README
+++ b/board/technexion/pico-imx7d/README
@@ -47,3 +47,20 @@ Remove power from the pico board.
 Put pico board into normal boot mode.
 
 Power up the board and the new updated U-Boot should boot from eMMC.
+
+Building U-Boot to boot with NXP 4.1 kernel:
+
+The NXP 4.1 kernel boots only in secure boot mode on mx7.
+
+Follow the next steps to enable secure boot:
+
+$ make mrproper
+$ make pico-imx7d_defconfig
+$ make menuconfig
+       -> ARM architecture
+       -> [*] Enable support for booting in non-secure mode
+       -> [*]   Boot in secure mode by default
+       -> Exit
+$ make
+
+Flash u-boot.imx using the imx_usb_loader tool.