There is currently no GUI for udp2raw on android.Make sure you have installed Terminal to run it.Your device has to be rooted,otherwise you cant use raw socket.

Download udp2raw_arm from https://github.com/wangyu-/udp2raw-tunnel/releases.

Copy udp2raw_arm to any dir of your internal storage .Copying it to SD card wont work.

1. run udp2raw_arm as usual, except you must change the -a option to -g

./udp2raw_arm -c -r 44.55.66.77:9966 -l 0.0.0.0:4000 -k1234 --cipher xor -g

2. find the generated iptables rule from udp2raw's output,add it manually by running:

iptables -I INPUT -s 44.55.66.77/32 -p tcp -m tcp --sport 9966 -j DROP

3. run udp2raw_ram without -g command

./udp2raw_arm -c -r 44.55.66.77:9966 -l 0.0.0.0:4000 -k1234 --cipher xor 

zoom-in if not large enough

If you android devie is not rooted, there are other workarounds exists:

https://github.com/wangyu-/udp2raw/discussions/497#discussioncomment-7516832