well, u can try this

- go here download U mobile flash file -> http://www.u.com.my/broadband/firmware-upgrade
- get your movistar flash file ready too ( if u already have it store in computer )
- plug in your ZTE MF190 into usb port
- close any dashboard which pop up
- run the U mobile  Flashing file
- once the update button ready can click leave it
- go to my computer -> Drive C -> Program File -> Window Service -> there is a folder -> copy everything out from that folder -> store it in some temporary places ( * u going to need it later )
- close u mobile flashing file
- run Movistar Flashing file
- wait for update button ready but dont click it yet
- go to my computer -> Drive C -> Program File -> Window Service -> there is a folder -> delete everything inside that folder -> Then paste * u mobile temporary file u copy just now in there
- click the update button in movistar flashing file
- wait for flashing to finish
- unplug your ZTE MF190 modem when flashing finish
- then uninstall the movistar dashboard + drivers in your computer
- replug in your ZTE MF190 in your USB port
- install the u mobile Dashboard in your computer
- enjoy