[Ramon]

Только что прошил 7500 MT-box через miniUSB (как раз твой случай). Идем пошагово:
1. Выбираем соответствующие файлы (MCU, PPM, CNT), выставляем соответствующие галки.
2. Жмем на кнопку "USB" (справа от окна "mode").
3. Жмем на "Flash" и кратковременно тыкаем конпку включения, тело должно при этом подцепиться.
В моем случае получилось вот что:
MTBOX: 00511ed99c - Nokia Flash/Repair v1_36
Box: ********************
Code: ********************
SN: ********************
Nokia Unlimited: 878 times started
SonyEricsson Trial: 10 left, each max 15min
FAILED to find USB Device.
Attach phone to usb port!
Switched to USB BUS
BB5 PM back Phone is in: Phone is not responding!
Processing File: rm249__03.50.mcusw
Boot...
CONNECT PHONE to USB and Power ON phone!
Pooling for phone...
\\?\nmwcd#vid_0421&pid_0106&if_oth#6&472eea3&5&00# {4f919102-4adf-11d5-882d-00b0d02fe381}
Sending ULO code
Sending UPDAPP code
Sending PASUBTOC code
Pooling for device removal...
Device removed
Pooling for ADL device...

%%%%%%%% ERROR BOOTING:
При этом выскочило окно:
"Неизвестное устройство"
Передергиваем АКБ, перезапускаем прогу, и вуаля:
Boot...
CONNECT PHONE to USB and Power ON phone!
Pooling for phone...
\\?\nmwcd#vid_0421&pid_0106&if_oth#6&472eea3&5&00# {4f919102-4adf-11d5-882d-00b0d02fe381}
Sending ULO code
Sending UPDAPP code
Sending PASUBTOC code
Pooling for device removal...
Device removed
Pooling for ADL device...
\\?\nmwcd#vid_0421&pid_0105&if_oth#6&698f928&1&00# {4f919102-4adf-11d5-882d-00b0d02fe381}
Erase[63.63 MB]...
erasing RAP [00000000 to 000006BF]
erasing RAP [000006C0 to 0001FFFF]
erasing RAP [00040000 to 000BFFFF]
erasing RAP [000C0000 to 0013FFFF]
erasing RAP [01000000 to 0111FFFF]
erasing RAP [00140000 to 00FFFFFF]
erasing RAP [01780000 to 018FFFFF]
erasing RAP [01900000 to 03FBFFFF]
erasing RAP [01120000 to 0177FFFF]
in 200.65s
Flash[15.81 MB]...in 115.74s
* * Processed file in 326.66 seconds
Processing File: rm249__03.50.image_f
Boot...
Pooling for ADL device...
\\?\nmwcd#vid_0421&pid_0105&if_oth#6&698f928&1&00# {4f919102-4adf-11d5-882d-00b0d02fe381}
Erase[0.00 MB]...
in 0.01s
Flash[9.51 MB]...Content page size is 128K
in 63.13s
* * Processed file in 63.31 seconds
Processing File: rm249__03.50.ppm_f
Boot...
Pooling for ADL device...
\\?\nmwcd#vid_0421&pid_0105&if_oth#6&698f928&1&00# {4f919102-4adf-11d5-882d-00b0d02fe381}
Erase[0.00 MB]...
in 0.01s
Flash[4.84 MB]...in 33.56s
* * Processed file in 33.75 seconds
Restarting device...
Pooling for device removal...
Device disconnected.
* * * Phone flashing done in 7:22 minutes
Post Flash serial tunning of phone....
Pooling mode for full factory set...
V 03.50/25-07-07/RM-249 (c) Nokia
IMEI: 357685011023071
Factory Default Settings...OK
Reset user code...Successfull, code is 12345
Что у тебя не так, не знаю, так как ты не привел лог.