busybox/examples/var_service/tftpd/run

#!/bin/sh

#exec >/dev/null
exec 2>&1
exec </dev/null

user=root # for bind to port 69

exec \
env - \
softlimit \
setuidgid "$user" \
udpsvd -v -c 10 -l localhost \
  0 69 \
tftpd /pub/tftpd_root