How to unlock your Huawei E173, E1750 or E1550 data card :
1. Download Universal Master Code.exe from the download link which is provided at the end of the article. Enter your 15 Digit IMEI number in Huawei tab, as shown in the below screen and press Calculate for Unlock Code and Flash Code.
2. Plug your data card with an unaccepted SIM to your PC.
3. For E173, It will prompt for an unlock code, just enter the Unlock Code you got from Universal Master Code.exe. (Your Huawei E173 modem is now unlocked and can be used with any another SIM after creating the profile).
Note : But, E1750 and E1550 modems does not prompt for unlock code, hence, you have to download HUAWEI_MODEM_Code_Writer.zip from the below link and continue to step 4.
6. Press ” Detect” and choose your modem type in dropdown list. Then press ” Accept”.
7. Press ” Unlock Modem “, a pop up window will appear asking you to enter the Unlock Code.
8. Enter the Unlock code from Universal Master Code in the field provided and click ” OK “.
9. Press ” Unlock Modem ” (Your Huawei modem E1750 or E1550 is now unlocked and can be used with any another SIM after creating a new profile).
Note : The above guide cannot be applied with Customized Firmware modem, to unlock customised firmware you need to flash the modem first, then it will accept the unlock code.