Please try this perl script with your IMEI (slot 1) and serial number:
perl fp3verifycode.pl --imei 123456789012345 --serial A1234567890
(The numbers can be found under “About phone” - “Model & hardware”)
This should print a string with 8 hex chars at the end for the verify code.
You might also check adb logcat when trying this, maybe there is some output from the OemUnlock code …
I cannot test it myself as I have unlocked mine directly after receiving it and before installing any updates.