The M028T is not compatible with OpenWrt or DD-WRT. Its Broadcom chipset has locked bootloaders. Do not attempt to flash non-official firmware – it will hard-brick the device.
WARNING: Do NOT download firmware from random file-sharing sites or Torrents. Unverified firmware can be malware, incomplete, or for a different hardware revision (brick risk). vodafone m028t firmware download
This is the safest method if you are using a Vodafone SIM card. The M028T is not compatible with OpenWrt or DD-WRT