The Hotwav Cosmos V21 was an improvement over previous Cosmos models, powered by the Spreadtrum SC7731GEA chipset and Android 6.0 Marshmallow. Despite its decent build and expandable storage, users across repair forums and tech groups began reporting “No Service” network drops, bootloops after resets, touch delays, and frequent Play Store crashes. These bugs became worse when customers unknowingly used the wrong SPD firmware. The official V21_20170627 build (687MB) is the verified repair firmware for this device, tested on both African and Asian variants. It restores full SIM, camera, and system stability, eliminating screen freeze, system UI pop-ups, and network registration failures.
Hotwav Cosmos V21 SPD Firmware Details
| Device Name | Hotwav Cosmos V21 |
|---|---|
| Chipset | Spreadtrum SC7731GEA |
| Android Version | 6.0 Marshmallow |
| RAM / Storage | 1GB RAM / 8GB ROM |
| Firmware Version | V21_20170627 |
| Build Date | June 27, 2017 |
| File Size | 687MB |
| File Type | .pac (SPD Upgrade Tool / ResearchDownload) |
| Flashing Tool | SPD Upgrade Tool |
Download Official Firmware for Hotwav Cosmos V21
Size: 687MB
Build Date: June 27, 2017
Chipset: Spreadtrum SC7731GEA
Android Version: 6.0 Marshmallow
Download Link: MediaFire Direct Link
Why Flash This Specific Firmware?
- Fix “No SIM / No Network” Issue: This build restores the baseband and NVRAM integrity that older V20 and V19 firmware corrupted, fixing the persistent “No SIM detected” and “Invalid IMEI” issues after a failed factory reset.
- Resolve Boot Freeze and UI Force Closures: Devices hanging at the COSMOS logo or showing “System UI has stopped” are fully revived by replacing boot and system partitions with verified 2017 factory images.
- Recover Camera & Flashlight Functionality: Restores original camera HAL; essential to fix “Camera cannot open” bugs or white-screen preview from incorrect drivers.
- Fix Touchscreen Lag & Edge Responsiveness: Restores correct SP7731GEA panel firmware to eliminate ghost touches and unresponsive corners experienced after improper updates.
- Repair App Crash, Google Play & Storage Errors: This version comes with the right Play Store integration package, repairing runtime permission loops and freeing blocked internal storage for app installation.
How to Flash the Firmware
Flashing the .pac firmware onto your Hotwav Cosmos V21 requires SPD Upgrade Tool:
- Setup: Install SPD drivers, extract firmware. Launch ResearchDownload and load the
.pacfile. - Flash: Click Start Download, power off device, hold Volume Down and connect to PC.
- Wait: Flashing completes in 7–10 minutes with a “Passed” message. Boot and confirm SIM, touch, camera, and battery behavior.
Full visual guide: How to Use the SPD Upgrade Tool to Flash Your Smartphone
