Download Android 4.1.2 Jelly Bean stock firmware for Jiayu S1 smartphone from here or here. Download another Jiayu firmware from here.
Archive name: S1-JYS1N011-20131219
Archive file size: 480 MB
Image file name: S1-JYS1N011-20131219.bin
Firmware: Stock Android 4.1.2 Jelly Bean
Support: Qualcomm APQ8064
Kernel version: 3.4.0
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