Match the exact model, region, and branch name. Similar model numbers are not the same device.
Firmware files are here on Inar Guide. Tutorials, flash tools and USB drivers are on FlashGuideHub.
The Positivo S421 is an entry-level smartphone powered by MediaTek MT6737M. Common user complaints include bootlooping and dead boot after failed updates or wrong flash, stuck on logo, touch not working post-flash, persistent FRP (Google) lock, and issues restoring after full format in SP Flash Tool. Using the matching firmware restores bricked/dead S421, fixes touchscreen and boot logo faults, and helps remove FRP lock or system instability.
Positivo S421 MT6737M Firmware Details
| Device Name | Positivo S421 |
| Chipset | MediaTek MT6737M (Quad-core, 1.25GHz, Mali-T720MP2) |
| RAM/Storage | 1GB/8GB (microSD expansion supported) |
| Display | 5.0″ LCD, 854×480 px |
| Camera | 8MP Rear, 2MP Front |
| Battery | 2000mAh removable |
| OS | Android 6.0 Marshmallow / 7.0 (varies) |
| Firmware Filename | Positivo_S421_MT6737M_05012017.zip |
| Firmware Version | 05012017 |
| File Size | 993MB |
| File Type | .zip (contains MTK scatter/SP Flash Tool files) |
| Flashing Tool | SP Flash Tool |
Warning:
Never flash scatter files from S421T or S421 (MT6737T or MT6735) on an S421 MT6737M—wrong firmware can cause black screen, permanent dead boot, or loss of touchscreen. Avoid “Format All + Download” options unless the device is seriously corrupted.
Download Official Firmware for Positivo S421 MT6737M
Restore soft-bricked, bootlooped, or FRP-locked Positivo S421 MT6737M using the factory scatter firmware (verified for this model).
Firmware:
📄 Filename: Positivo_S421_MT6737M_05012017.zip
📦 Size: 991.86MB
⬇️ Download Link (MediaFire)
How to Flash the Firmware
- Extract Positivo_S421_MT6737M_05012017.zip to access scatter and firmware files.
- Install MTK VCOM USB drivers (Windows). Download and open SP Flash Tool.
- In SP Flash Tool, load the scatter file. Power off phone, remove battery, then connect USB.
- Click “Download” to start flashing; wait for “Download OK” message. First boot after flash will take longer than usual.
- If phone remains dead, try only “Firmware Upgrade” mode, or check battery and cables.
For detailed SP Flash Tool video and troubleshooting tips, visit: this MTK flashing guide.