When the firmware update process Xiaomi Redmi 3S to be completed, the error message dummy bin not found appears in XiaoMi Flash Tool. Based on experience, the issue occurs if you use Fasboot ROM MIUI 8 Global Stable v126.96.36.199. Follow the step by step below to fix the dummy.bin not found problem.
- Open the Fastboot ROM folder that has been extracted.
- You will find a dummy.img file, just rename it to dummy.bin.
- Restart your PC and then repeat flash.
I hope in the future Xiaomi Team Developer fix this bug.