rtl8821cu mdev rule for automatic usb modeswitch

board/raspberrypi/device_table.txt

@@ -1,4 +1,9 @@
 # <name>				                <type>	<mode>	<uid>	<gid>	<major>	<minor>	<start>	<inc>	<count>
+
+# ssh keys
 /etc/ssh/ssh_host_ecdsa_key				f	    600	    0	    0	    -	    -	    -	    -	    -
 /etc/ssh/ssh_host_ed25519_key			f	    600	    0	    0	    -	    -	    -	    -	    -
-/etc/ssh/ssh_host_rsa_key				f	    600	    0	    0	    -	    -	    -	    -	    -
+/etc/ssh/ssh_host_rsa_key				f	    600	    0	    0	    -	    -	    -	    -	    -
+
+#rtl8821cu usb modeswitch script
+/lib/mdev/rtl8821cu_usb_modeswitch.sh   f       755     0       0       -       -       -       -       -

board/raspberrypi/post-build.sh

@@ -18,17 +18,6 @@
 #   - Installing packages (use rootfs overlay or a package .mk instead)
 #   - Modifying files outside $1
 
-set -e
-
-TARGET_DIR="$1"
-
-# Example: ensure /etc/hostname exists with a default value
-if [ ! -f "${TARGET_DIR}/etc/hostname" ]; then
-    echo "rpi-common" > "${TARGET_DIR}/etc/hostname"
-fi
-
-# Example: remove unnecessary documentation to save space
-rm -rf "${TARGET_DIR}/usr/share/man"
-rm -rf "${TARGET_DIR}/usr/share/doc"
-
-echo ">>> Common post-build script completed"
+# Add usb_modeswitch mdev rule
+grep -q "usb_modeswitch" "$TARGET_DIR/etc/mdev.conf" || \
+    echo '$PRODUCT=bda/1a2b.* root:root 0660 */lib/mdev/rtl8821cu_usb_modeswitch.sh' >> "$TARGET_DIR/etc/mdev.conf"

board/raspberrypi/rootfs-overlay/lib/mdev/rtl8821cu_usb_modeswitch.sh

@@ -0,0 +1,3 @@
+#!/bin/sh
+[ "$ACTION" = "add" ] || exit 0
+usb_modeswitch -v 0bda -p 1a2b -c /usr/share/usb_modeswitch/0bda:1a2b &