How to upgrade your HTC Android Phone with RUU

RUU stands for ROM Update Utility. In general the update procedure is, install HTC Driver, Connect your phone to Computer in Normal Mode or Fastboot Mode, Run the RUU and follow instructions showing on software. But it will work only when you are using same CID ROM, or your phone is super CID or you're using gold card. Here I'll try to describe the update procedure in different conditions.
Determine Your Phone CID

CID stands for Customer ID. HTC implemented this check to prevent flashing other region firmwares. For example, if you have a phone which CID belongs to Singapore, you normally can't update ROM from other region like EURO/USA/CHINA etc. You've to use same region firmware. Remeber that, SIMLOCK is not related to CID, if you sim unlock a phone still you may not be able to flash other region ROM. But unlocking tools like XTC, HXC etc does CID unlock too as well as SIM unlock. To Determine your phone's CID I've made a small script. Download getcid.rar from attachment, extract, connect the phone to Computer in Fastboot Mode, run getcid.bat. It'll show phone's current CID.

SUPER CID

Super CID is a Universal CID. If your phone has superCID, you can flash any ROM from any region. To make your phone superCID, you must S-OFF your phone. After you have succesfully S-OFF your phone use the supercid script (check attachment) to get superCID. Download supercid.rar, extract, connect the phone in Fastboot Mode to Computer, run suerpcid.bat and its done. Now you can flash any ROM.

CHANGE CID

Another method is Changing the CID (if you don't want superCID). Still you need S-OFF to do that. After you've successfully S-OFF your phone, send this commant in Fastboot mode fastboot oem writecid CIDNAME. For example you have e phone from a CID from UK and now you want to flash it with a German ROM which CID is HTC__102. To change the CID, your command will be fastboot oem writecid HTC__102

GOLD CARD

Its another method to flash different region ROM and you don't need S-OFF or superCID. Gold Card is a special microSD card that will turn your phone into temporary superCID state when it is inserted. With GoldCard you can flash only same or higher hboot version ROM's. You can use revskills, XTC Clip, HXC Dongle, AXE Box, Micro Box, LGE Tool etc to make GoldCard's for different models. After you've made a GoldCard, insert it to your phone, connect your phone to Compuer in normal mode or fastboot mode and run desired ROM as usual. CID check will be skipped.

WARNING : we have mentioned some professional tools like XTC Clip, HXC Dongle, AXE Box, Micro Box, LGE Tool etc just for reference. This is not the support section for them, rather they have different sections/forums and dedicated supporters are there to help you. So if you have any questions/problems operating those tools please post Here a Commnent

Get CID

Super CID