Upgrading factory firmware to something else (like OpenWrt, or DD-Wrt) is quite often complex and painful process.
But not always.
To help people who want to move from factory firmware to OpenWrt, I did this process step-by-step, capturing all screens and messages.
I used TP-Link TL-WR1043ND wireless router, which is based on Atheros chipset, and can be flashed directly from web interface, without need to setup tftp server or other trick.
Firmware upgrade for TP-Link TL-WR1043ND
Hardware version is TL-WR1043ND v1.6
Before going further, make sure that hardware version of your device is compatible with OpenWrt firmware.
1. To upgrade from TP-Link TL-WR1043ND factory firmware to OpenWrt, you need first to reset all settings to default.
Go to System Tools - Factory Defaults. Click on "Restore" button to reset settings to factory.
2. You will see message "Factory settings restored successfully!", and your router is restarting
3. Default IP address for TP-Link WR1043ND router is 192.168.1.1
Netmask is 255.255.255.0
If you flash from Windows (I used Windows XP for this testcase), go to Network Connections and change IP address for your computer to static, from the same subnet as your router has.
For example: 192.168.1.200
Ping your router from command line (>ping 192.168.1.1) to make sure that router is accessible.
Disconnect all cables from router except cable from tour PC (other computers, WAN cable from provider or cable/DSL modem)
4. Open in web browser web interface of your router.
Go to System Tools - Firmware Upgrade. Enter filename for firmware downloaded previously to you disk.
You need to download before doing this step firmware from /backfire/10.03.1-rc4/ar71xx/ repository.
Version to flash from factory firmware: openwrt-ar71xx-tl-wr1043nd-v1-squashfs-factory.bin
When OpenWrt Backfire 10.03.1 is released, you need to use repository from that final release.
5. You will see message "Please wait until system reboots..."
Never flash your router via Wi-Fi (wireless) connection. You can damage your router
Never turn power off for your computer or router during flashing procedure.
This would brick your router.
6. Wait until you see message "Software Upgraded Successfully! Restarting..."
Do not switch off computer or router until you see this message.
From my experience, this procedure with WR1043ND is quire fast, much faster comparing to other routers which I flashed before. It takes appx. 2-3 minutes.
7. Wait a little bit until your browser rebooted.
And open again address 192.168.1.1 in your browser
Before this you can ping 192.168.1.1 from command line to make sure interface is up and responding.
You will see OpenWrt LuCI web screen with login.
Click on "Login" button, without entering any password.
8. Go to System - Admin in menu, and change default password to your own password.
Go to Overview - Hello screen, and see greetings from OpenWrt/LuCI and its developers.
Your system is up and running.
You can start configuring it up to your needs.
Версия этого How-To на русском языке: FAQ: как установить OpenWrt на маршрутизатор TP-Link WR1043ND