Wait for the display to show and then turn the unit off and back on using the On/Standby button on the front panel. Method 2: USB Update
For the Onkyo TX-NR646 Go to product viewer dialog for this item.
Since the unit no longer receives updates, some newer streaming protocols or security protocols from Apple might not be supported. Try using a wired connection or using a dedicated streaming device (like an Apple TV or Roku) connected to the HDMI input instead of relying on the receiver’s internal network features.
Plug the USB drive into the front-panel USB port of the TX-NR646. Press on your remote control. Navigate to Misc > Firmware Update . Select Update via USB . Confirm the update when prompted.
This is the most reliable method if you have the correct file. txnr646 firmware update 2021
Onkyo strongly recommended performing the update via for the NR646 in 2021, as the over-the-network (internet) update servers for this legacy model were becoming unreliable.
DSP settings initialized. Fix: Re-run AccuEQ Room Calibration (microphone included with the receiver).
The most significant update for the Onkyo TX-NR646 in the modern era arrived on December 2, 2020
: Ensure no audio or video is actively playing through the receiver. Wait for the display to show and then
This method is because the official update servers are offline. If you attempt it, the "Update via NET" option will likely be grayed out or will fail to find an update. Even when it was functional, the process could take over an hour depending on network conditions.
Before initiating the update process, prepare your equipment to avoid system corruption.
: Fixes a software glitch that prevented song information and track metadata from displaying properly during SiriusXM radio playback.
Extract the files to the root of the USB drive and initiate the update through the receiver's menu. TX-NR646- Owner's Manual - Onkyo Product Support Try using a wired connection or using a
: Plug the USB into the receiver. On the front panel or remote, go to 8.1 F/W Update Update via USB . The process typically takes 30 to 40 minutes Completion
: Select Update and press ENTER . The process takes roughly 20–30 minutes .
| Error Code / Symptom | Likely Cause / Solution | | :--- | :--- | | "Firmware Update" grayed out | The receiver is busy booting up; wait a few minutes and try again (Search Results 10). | | *-01 , *-10 (USB method) | USB storage device not found. Check if the USB is properly inserted, has no security locks, and is formatted correctly (Search Results 10). | | *-05 , *-13 , *-20 , *-21 | The firmware file is , is corrupted, or is for a different model. Retry the download and ensure the files are in the root directory (Search Results 10). | | *-02 , *-03 , *-04 , *-11 | Internet connection error. Check if your router is on and the Ethernet cable is secure. Reset your router and try again (Search Results 15, 16). | | Other Errors | Disconnect the AC power cord from the receiver, wait 30 seconds, plug it back in, and retry the update from the beginning (Search Results 10, 15). |