this is how to make Android bootable SD card from update.img.
if you need available bootable SD images, please refer Rock/SD images.
1. update.img for SD boot 2. A sdcard (4G at least) 3. A sdcard reader/writer 4. Windows PC
Make the Boot Disk under Windows
1. Download the tool to make upgrade disk and unzip it http://dl.radxa.com/rock/tools/windows/SD_Firmware_Tool.zip 2. Insert the reader to pc and insert the sdcard to reader 3. Find SD_Fireware_Tool.exe under SD_Fireware_Tool and click it. See PIC_1 4. Select the insert sdcard under "Choose removable disk" Item. See PIC_1 5. Select "SD Boot" (Note:Select only this item). See PIC_1 6. Click "Firmware" button to choose the image just download and unzip.See PIC_1 7. Click "Create" to begin. when complete, there will be a dialog to tell you success
Boot system from sdcard
1. Power off the RR 2. Insert the sdcard 3. Power on the RR, the process starts and the process likes the android system first boot.