Setup diag-router FunctionFS gadget on pmOS phone with already configured USB gadget

setup-diag.sh

#!/bin/sh

set -x

G1="/sys/kernel/config/usb_gadget/g1"

# turn off the gadget
UDC_NAME=$( cat $G1/UDC )
echo "" > $G1/UDC
sleep 1

# cleanup prev setup
umount /dev/ffs-diag
rm -rf /dev/ffs-diag

# create FunctionFS function
mkdir -p $G1/functions/ffs.diag

# First config (c1) is already pmOS's USB gadget.
# Use Config #2
C2="$G1/configs/c.2"

mkdir -p $C2
mkdir -p $C2/strings/0x409

echo "diag_dun" > $C2/strings/0x409/configuration
rm -f $C2/ffs.diag
ln -s $G1/functions/ffs.diag $C2

echo "Create/mount /dev/ffs-diag"
mkdir -p /dev/ffs-diag
mount -t functionfs diag /dev/ffs-diag

# turn on the gadget
sleep 1
echo $UDC_NAME > $G1/UDC