With the recently released Tizen 2.1 Beta you might want to flash it to your reference device. Well here are the instructions to do just that.
 

Requirements

• Tizen 2.0 alpha or later version loaded RD-PQ or RD-210
  • If you are not sure which is your device, please see here:
    • Pictures of Tizen Reference Phones (English)
    • Pictures of Tizen Reference Phones (Korean)
• lthor (flashing tool for Linux)
  • See Installation section on http://source.tizen.org/documentation/flash-image-device

Installation

For RD-PQ

1. Download following System and Platform images:

   http://download.tizen.org/releases/system/Tizen_RD-PQ_System_20130423_1.tar #System files

   http://download.tizen.org/releases/2.1b/tizen-2.1_wifi_20130505.1/images/RD-PQ/RD-PQ-tizen-2.1_20130505.1.tar.gz #Core Application Preloaded

   http://download.tizen.org/releases/2.1b/tizen-2.1_wifi_20130505.1/images/RD-PQ-REF/RD-PQ-REF-tizen-2.1_20130505.1.tar.gz #Reference Appliaction Preloaded

   • NOTE: Core Application image is not tested. More on Core/Reference Application
2. Flashing System Image

   lthor Tizen_RD-PQ_System_20130423_1.tar

3. Flashing Platform Image

   lthor RD-PQ-tizen-2.1_20130505.1.tar.gz #Core App Preloaded

   or

   lthor RD-PQ-REF-tizen-2.1_20130505.1.tar.gz #Reference App Preloaded

For RD-210

1. Download following System and Platform images:

   http://download.tizen.org/releases/system/Tizen_RD-210_System_20130423_1.tar #System files

   http://download.tizen.org/releases/2.1b/tizen-2.1_wifi_20130505.1/images/RD-210/RD-210-tizen-2.1_20130505.1.tar.gz #Core Application Preloaded

   http://download.tizen.org/releases/2.1b/tizen-2.1_wifi_20130505.1/images/RD-210-REF/RD-210-REF-tizen-2.1_20130505.1.tar.gz #Reference Appliaction Preloaded

2. Flashing System Image

   lthor Tizen_RD-210_System_20130423_1.tar

3. Flashing Platform Image

   lthor RD-210-tizen-2.1_20130505.1.tar.gz #Core App Preloaded

   or

   lthor RD-210-REF-tizen-2.1_20130505.1.tar.gz #Reference App Preloaded

Post Flash Guide

The device will be automatically rebooted after successful installation. Please note that Tizen 2.1 Beta does not contain the hardware acceleration binaries so they must be downloaded and installed manually.

Mali DDK for Tizen 2.1 Beta is available HERE.

Note: Mali DDK in official guide[1] is not compatible with Tizen 2.1 Beta.

Enable 3D Acceleration on Tizen 2.0

Troubleshooting

• lthor

If you are unable to connect lthor to the device on Ubuntu (12.10 or 13.04) please follow the instructions to solve the issue.

• enlightenment has closed unexpectedly

This error message may occur on start-up if Mali DDK binaries for Tizen 2.0 Magnolia have been installed on Tizen 2.1 Beta. To platform image has to be flashed again to fix the issue.

Source Tizen Wiki