How to Fix Sonoff Smart Switch Not Updating Firmware
- unstable network during OTA
- insufficient device state prep
- temporary update service timeout
Problem Description
Your SONOFF smart switch shows a firmware update available in eWeLink, but the update fails or never completes. The progress bar may stall, the app may show an error message, or the device may reboot without applying the new firmware. Firmware updates require a stable WiFi connection and continuous power throughout the 1-4 minute process.
Why This Happens in Real Homes
Why this happens in real homes usually comes down to environment and timing, not instant hardware failure. Firmware update attempts fail or stall before completion. The pattern people actually report is Update stuck, download fails, and version unchanged after reboot
The most common real-world triggers are unstable network during OTA, insufficient device state prep, and temporary update service timeout. The fix is most reliable when the sequence is followed exactly: Check network stability before OTA, then Prepare clean update state, then Retry controlled firmware push. After the repair, run multiple command and automation checks so the issue does not reappear later in the day.
Symptoms
- Update stuck
- download fails
- version unchanged after reboot
Recognize these? Here's what usually causes it.
Common Causes
- unstable network during OTA
- insufficient device state prep
- temporary update service timeout
Most fixes happen in the first 3 steps.
Do not interrupt power during firmware flash cycles.
Tools & Requirements
Step-by-Step Solution
Check the device's current firmware version
In eWeLink, tap the SONOFF switch > ··· (three dots) > Device Info. The firmware version appears as a number like v1.4.0 or v3.5.1. Note this down. Then go to ··· > Firmware Update. If the button says 'Up to date': no update is available for your specific model. SONOFF releases firmware per device model — a BASICR4 update does not apply to a MINIR4. If the update button is greyed out: the device is offline and cannot check for updates.
Verify the device is online and connected
Firmware updates download over WiFi directly to the switch. The device must be online in eWeLink (green status, not greyed out). If offline: check WiFi connectivity first. The device also needs a stable connection throughout the download — typically 1-4 minutes. If the device has a weak signal (check RSSI in Device Info — below -75 dBm is marginal), move a WiFi access point closer before attempting the update. A dropped connection mid-download can corrupt the firmware.
Keep the device powered during the update
Do not flip the breaker, wall switch, or disconnect power during a firmware update. The switch writes new firmware to its flash memory — interrupting this process can brick the device (stuck in a boot loop with a flashing LED that never stops). The eWeLink app shows a progress bar during the update. Wait for the 'Update successful' confirmation before touching the device. Updates on the BASICR4 take about 90 seconds, the MINIR4 about 2 minutes, the 4CHPROR4 about 3 minutes.
Restart eWeLink if the update fails
If the update starts but fails with a generic error: force close eWeLink completely, reopen it, and retry. Common causes: your phone switched from WiFi to cellular during the update (keep your phone on WiFi), the eWeLink cloud server timed out (retry in a few minutes — server-side issues resolve on their own), or the app lost its session token (logging out and back in fixes this). Do not retry more than 3 times in a row — repeated failed flashes stress the device's flash memory.
Factory reset the switch if updates fail repeatedly
If a specific switch will not accept firmware updates despite being online with good signal: factory reset it. Press and hold the device button for 5-10 seconds until the LED blinks rapidly. Re-pair the device in eWeLink (+ > Quick Pairing). After pairing, immediately check for the firmware update again. A fresh pairing clears any corrupted configuration or partial firmware state that was blocking the update process. Your scenes and schedules linked to this device will need to be recreated since the device gets a new ID.
Quick Solutions
Still having issues? This is usually the deeper cause below.
If the device became unresponsive after a firmware update, a factory reset usually clears the corrupted state — the update itself is rarely the root cause.
OTA reliability improves when run under stable connectivity and clean device state.
This issue almost always looks more complex than it is — the majority of cases trace back to a single setting, a stale credential, or a default that shipped wrong.
- unstable network during OTA
- insufficient device state prep
- temporary update service timeout
Before you go — try one of these (they fix most cases).
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Official Manufacturer Manual
SONOFF provides official product documentation through their online manual rather than downloadable PDF. Access setup guides, troubleshooting steps, and product specifications for your Sonoff Firmware Update Failures.
Source: sonoff.tech
Need More Help? SONOFF Support
Note: The contact information below connects you directly to SONOFF's official customer support team, not Trunetto. They can help with warranty claims, device replacements, and advanced technical issues.
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