sorry for my poor English

, I'm Chinese. I asked a guy about how the defy unlocked(after repair). He said the JS(the man who can fix the dead phone but always want a HIGH pay) only flashed a file(not sbf) into his phone with some tools(not the rsd), the whole procedure without any hardware replacement. Then the JS flashed a uk 2.2sbf with rsd, but in the model col of rsd, it shows SE TI omap 3630. And now his boot loader is unlocked.
So I think the file flashed by JS is the key to unlock, after the flash, the phone will become an eng-board, and the IMEI will become to 000000123456(or 0000001123456 etc).
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OK, I confimed a guy who repaired his defy in Shang Hai moto offical repair service site (not the JS), and his bootloader is unlocked now. But the different with above mentioned is his IMEI not changed (not 000000123456 etc). In rsd is also SE Flash OMAP3630, and the hardware is still not changed.
I don't know how they flashed the file, maybe by the usb cable or the usb-to-serial cable...