Downgrade Lumia 900 DLOAD to Qualcomm??

Currently i have lumia 900 phone with dload BL, but the marketplace apps is very few. So i want to flash custom rom for installing XAP files. Is there any way to change dload bootloader to qualcomm without disassembling phone? My friend have atf box, can he help me flash phone? Because i don't need to disassemble. Sorry for poor english and thank you for help. How can i flash custom rom without disassembling phone? Have only ATF box.

Lumia 900 boot-loader can only be changed via Test Points = disassemble.
No other way for now.

Thanks, but why in Vietnam forum no one told about testpoints? They already flashed custom rom to lumia 900 only with ATF, without testpoints.

They might not have mentioned this to you, but I confirm you that it is
via Test Points.