设备无法切换到下载模式

COULDN'T CHANGE PHONE TO DOWNLOAD MODE
This error can have multiple causes.

One cause is the phone has one or more problems switching from DIAG mode to DLOAD (Downloader) mode after successfully receiving the command to do so. Specifically, this is CMD_CODE 58 (Switch to Downloader). QPST has to switch the phone offline (CMD_CODE 68) and then into downloader mode using CMD_CODE 58. The target may not be processing one of those mode change commands properly. To verify, go to the QPST Bin directory, which is typically in "C:\Program Files\QPST\Bin" and search for a file named "Dload_COMx.dbg", where x = the COM port number QPST was using for the previous download attempt. Once you find that file, attach it to your Case for analysis.

If you have QXDM, you can manually command the phone to switch to DLOAD mode by sending the following command:

SendRawRequest "0x3A"

The target should switch to DLOAD mode and indicate that on the UI as well as on the COM port QPST is monitoring. In this state, you can disable the "Auto Backup/Restore" option on QPST and proceed to flash upgrade the target without backing up NV. However, before you do this, it is necessary that you have already created or received a QCN backup file for your particular target. QCN backup files contain target-specific calibration data and can be created manually by using QPST Software Download's BACKUP tab. If you need the QCN for your target, create a Case and include the serial number. Qualcomm can provide the latest QCN backup file from when the device was last calibrated at our factory. Once an upgrade from DLOAD mode completes, the QCN will need to be restored to the device manaully using QPST Software Download's RESTORE tab.

Another possible cause is that once the phone is told to switch to DLOAD mode by QPST, the USB virtual COM port changes to a new port. In this situation, it is helpful to observe the Windows Device Manager on the Ports branch to see if the target re-enumerates on a different port. If it does, QPST will allow you some time to manually browse and reselect the correct COM port before it displays this message. A future version of QPST will automatically follow the ports and select the correct one in these conditions. However, for now, you must always manually connect QPST to the COM port.


The Hardware Watchdog is disabled
QPST needs the Hardware WatchDog enabled for reset and entering into download mode.


COM error 80004005 during SetPhoneMode
When you get this error (captured in the debug file of the COM port to which you're trying to download the software, see example below) generally it is because of one of these reasons:

• The phone won't switch to offline mode because some phone task is voting against the change.
• The phone switches offline, but won't switch to download mode.
• The request to switch to offline or download mode causes the phone to crash or reset.
• The user is trying to download to a WinMobile phone over TCP/IP. They would have to reconfigure the phone's USB to use composite mode (use the switchUSB application on the phone).
• The change to download mode was successful but the phone re-enumerated on a different COM port.

Example of debug file with this error:

QPST Software Download 2.7.0.312 DEADD00D SURF1000-800 M6290A-KPRZL-1.2.0070
Modem file (and path for flash programmer): D:\Um\build\ms\bin\KPRZL\amss.mbn
Flash Programmer file: D:\Um\build\ms\bin\KPRZL\NPRG6280.HEX
Sending Diag Ping Command
Jumping to Download Mode
COM error 80004005 during SetPhoneMode
Download end, status 103, error 115
Exit multi-image download with status 0x00000000