1. Format your SD card to FAT32.
2. Place HERAIMG.nbh into your SD card.
3. Hold the camera button then press the soft reset button while holding the camera button.
4. Press the down volume when it asks you to press something.
If this doesn't work, it means either:
1. Your SD card isn't fast enough. You can try partitioning the SD card so that it only has a small amount of space formatted. This can be read faster by the bootloader.
2. You don't have a HERAIMG.nbh file in your SD card.
3. Your HERAIMG.nbh was made with a small number in the "version" number.
4. Your SD is a SDHC. The driver that allows SDHC compatibility is not loaded in the bootloader. Buy a cheap little 1GB card to flash with.