W910i downgrade

Hello,my objective is that I want to downgrade my w910i from r1fa035 to r1fa030, unlocked by code and debranded by modifying some XML file.The instructions I found was a2uploader, main and fs. And gordon's gate. So I add the main and fs, and press flash right? Holding c and so on. I get A 101d error hdr block. What do I do?Also do I have to add XML files to prevent a customization error?Thanks,

Heya!!
Try this:
1st: Using A2uploader, upload customize_upgrade.xml file, on this route: tpa/preset/custom
2nd: Discconect from A2uploader, turn your phone on, wait for uploading phone system, then turn ur phone off.
3th: Finally Connect your phone to SEUS program (Sony Ericsson update Service) and you MUST UPDATE your phone (in fact you'll get r1fa030 firmware).
Good Luck!!!