Require 1000 mA or above power adapter to supply all device that connect into raspberry pi.
Require SD card minimum 1 GB class 6 or above, SD with class 4 it's not recomended
To get more space in root to install more openwrt module/app, you can resize second (mmcblkop2) partition that have ext 4 type with gparted (linux) or partition magic (windows)
Don't resize first partition in ur SD card (fat partition), it contain boot and mbr code...so dont change it at all
Login via browser/ssh to 192.168.1.1 with username: root pass: raspberryopenwrt
main issue: