Since there is not a proper thread containing the exact procedure for this device I'm going to explain it a little bit in detail, specially based on this device different things that doesn't have other android phones:
1. First we need to find a micro SD, normally this device comes with a 2gb Sandisk micro SD, this will be fine.
2. We need to format the microSD to FAT32, so remember to save your files before going on.
3. After the format, we need to create a GoldCard with this SD Card. Basically this is a "transformation procedure". You can find the method here: http://forum.xda-developers.com/showthread.php?t=572683 but I'm going to explain it based on Tattoo
Creating the Gold Card:
4. We need the android-sdk tools, we can find them here: http://developer.android.com/sdk/index.html download them, and unzip in a folder maybe in C:\androidtools
5. Go the the Command line (Start->Execute->write cmd and OK), and there you should find where you unzip the android-sdk tools, example cd c:\androidtools\tools
6. Run this command "adb shell cat /sys/class/mmc_host/mmc1/mmc1:*/cid" if you had the microSD in the drive you will find a long number like:
7. Go to this page to reverse it: http://hexrev.soaa.me/ and copy the code reversed:
In our example it will be: 00544d5107943247039c7d22bd002653
8. Go to this page to generate your GoldCard image: http://psas.revskills.de/?q=goldcard
And put your reversed number and you email. You will receive an email with a file called "goldcard.img"
9. Now you need an Hex editor like HXD. Download it from: http://download.cnet.com/HxD-Hex-Edi...html?tag=mncol
10. Exactly the same as the instructions I pasted above:
11. Install and launch HxD Hex Editor program. (make sure you use "Run as Administrator" under Vista and win 7)
12. Go to Extra tab > Open Disk. Under Physical disk, select Removable Disk (Must be your SD card), uncheck “Open as Readonly), click OK. (BEWARE, MUST BE UNDER PHYSICAL DISK NOT LOGICAL DISK, THIS MISTAKE MADE ME BIG PROBLEMS)
13. Go to Extra again, Open Disk Image, open up goldcard.img which you’ve saved/unzipped earlier.
Now, you should have two tabs, one is your removable disk, the other is goldcard.img. Press OK when prompted for “Sector Size” 512 (Hard disks/Floppy disks), click OK.
14. Click on goldcard.img tab. Go to Edit tab > Select All, edit tab again > copy.
15. Click on the “removable disk” tab. Select offset (line) 00000000 till offset (line) 00000170 (including the 00000170 line), click on Edit tab and then Paste Write.
16. Click on File > Save. now you can exit the program.
17. Now with the gold card created (the microSD transformed) we must reboot the HTC Tattoo. When we press the "reboot" button we must press nearly at the same time the POWER OFF and VOLUME DOWN buttons at the SAME TIME!!!! He will enter a new menu called HBOOT
18. We press back button to go to fastboot USB mode
19. Now we have to start the flashing utility for example: http://rapidshare.com/files/29251709...d_NoDriver.exe
This is done the 19th Decembre 2009, but maybe on the future there will be newer flash releases so this file will be replaced for the newer one.
19.1 If we get either Error 170 or 171 in the flashing process follow this other guide to solve this issue: http://forum.xda-developers.com/showthread.php?t=646663
20. The Flash will start we must wait, its better to do this process with 100% battery left
21. After 10 minutes, the flash will be done, and the HTC will reboot automatically with the Flashing done and everything OK!
Latest Official WWE Flashes for HTC Tattoo: