overlays on 4.17 need new device tree compiler from git

diff --git a/README.md b/README.md
index fe50d98..6e83077 100644 (file)
--- a/README.md
+++ b/README.md
@@ -23,7 +23,6 @@ to use device trees, do something like:
        dmesg -w &
        ./overlay-load.sh /boot/overlay-user/gpio-led.dtbo
 
-
 To load kernel module for i2c sensors without writing device tree
 echo module_name address into i2c bus:
 
@@ -32,3 +31,23 @@ echo lm75 0x49 > /sys/bus/i2c/devices/i2c-1/new_device
 
 
 i2c-usersapce/ contains random i2c userspace device drivers
+
+
+If you get following error when using armbian-add-overlay
+
+Missing dtc compiler in kernel headers directory. Please reinstall the kernel headers package
+
+then you are missing /lib/modules/$(uname -r)/build/scripts/dtc/dtc
+For overlay to work on 4.17 kernels you need recent dtc compiler from:
+
+       git clone https://git.kernel.org/pub/scm/utils/dtc/dtc.git
+
+which in turn needs bison and flex to compile:
+
+       apt-get install bison flex
+
+type make to compile it and create symlink to it:
+
+dpavlin@cubieboard2:~/linux-gpio-pinout/dtc$ sudo ln -sfv `pwd`/dtc /lib/modules/$(uname -r)/build/scripts/dtc/dtc
+‘/lib/modules/4.17.14-sunxi/build/scripts/dtc/dtc’ -> ‘/home/dpavlin/linux-gpio-pinout/dtc/dtc’
+