I have been attempting to get the USB Mass Storage (Qualcomm) bootloader mode with my Lumia 800 without luck.
I feel as though my situation may be a little bit different, because I am using a completely new, un-updated device. Here's the info from the Diagnostics app:
Diag App Version: 188.8.131.52
Firmware Rev: 1600.2475.7720.11414
Radio HW Rev: 8255
Radio SW Rev: 1.6.00.24
ROM Lang: 0809
ROM Vers: 7.0.7720.0
OEM Dev Name: RM-801 EU 222
Mobile Op: 000-GB
Mobile Dev Name: Lumia 800
Device HW Rev: 112.1402.2.3
Bootloader Vers: 184.108.40.206
Chip SOC Vers: 0.74.2.1
I try all the different combinations, but they all lead to either a normal bootup, or my device being recognized as only a 'HID-Compliant Device' for about 10 seconds, and then it vibrates and reboots normally.
The hardware IDs in the Device Manager are:
I see no DLOAD anywhere, and Linux shows up as a Microsoft USB Device when it does the 10-second dark screen mode.
Any ideas? Thanks.