MCX A57，A87 fastboot manual
Note：
This method is only applicable to: users to upgrade failure, and the mobile phone hold to the boot screen or only find the ADB interface.
Step：
1、 Install the battery to the mobile phone；
2、 Hold the volume down key, then press the boot key about 2 seconds, wait for mobile phone to vibration, then loosen the boot key button, but volume down key don't loosen;；
3、 Mobile phone and computer use USB cable connection (keep the volume key press and hold), and then open the 'device manager ", can find "Android Devices'' Android ADB Interface", as the FIG：
4、Decompress fastboot.zip, copy the system.img,boot.img,userdata.img&recovery.img files of the software package into the fastboot folder ,then double click ‘download.bat’ and loosen the volume down key, to start writing boot.img, system.img,userdata.img and recovery.img files, write is completed, the computer screen will prompt" Press any key to continue... ' ,as the FIG
