There are two official methods to apply the txnr646 firmware update 2021: via network (Ethernet or Wi-Fi) or via USB. Onkyo recommends USB for the most reliable results, especially if your receiver currently has very old firmware.
Because Onkyo’s network servers are sometimes offline for legacy devices, USB is the safest method for the 2021 update. txnr646 firmware update 2021
Step 1: Go to Onkyo’s official support page (search "Onkyo TX-NR646 firmware").
Step 2: Download the 2021 file named ONKAVR_646_2130-1010-0200.zip.
Step 3: Extract the folder. You will see a file named ONKAVR646_213010100200.bin.
Step 4: Copy this .bin file to a FAT32 formatted USB drive (not NTFS or exFAT). The drive should be 2GB to 16GB; larger drives often fail.
Step 5: Turn off the TX-NR646. Insert the USB into the service port (not the front USB – use the rear panel port labeled "USB/Service").
Step 6: Hold down the "CBL/SAT" button on the front panel and press "STANDBY/ON".
Step 7: Release the CBL/SAT button once "USB UPDATE" appears on the display.
Step 8: Wait 20–30 minutes. The unit will restart twice. Do not touch anything. There are two official methods to apply the
A: No. Speaker calibration settings are preserved. However, network and HDMI settings may reset to factory defaults. It’s important to set realistic expectations
A: No. Onkyo does not provide downgrade firmware. Installing older versions will cause a version mismatch error.
It’s important to set realistic expectations. The 2021 update does not add:
If you need those features, you must upgrade to a newer model like the TX-NR696 or TX-NR7100.