MR3020 firmware installation error code 18005

Hi,

The Firmware Upgrade gave the error:

"Error code: 18005
Upgrade unsuccessfully because the version of the upgraded file was incorrect. Please check the file name."

Steps taken:
- Downloaded [stable.openwrt.piratebox.de]
- Firmware Upgrade - Choose File - ar71xx_AA/openwrt-ar71xx-generic-tl-mr3040-v1-squashfs-factory.bin
- Upgrade - gave the above error

Hardware TL-MR3020
Firmware Version: 3.12.1 Build 120320 Rel.42138n
Hardware Version: MR3020 v1 00000000

thx

Julien