Epson WF-7840 Firmware Upgrade: Third-Party Ink Cartridges Not Recognized After Update (Rollback Options and What to Try Next)

Question: I upgraded the firmware on my Epson WF-7840 and now my third-party ink cartridges aren't recognized. I'm not doing sublimation-just regular printing-but the printer has been unusable since last week. Is there any way to fix this?

I accidentally upgraded the firmware on my Epson WF-7840. After the update, my third-party cartridges are no longer recognized, so the printer is basically dead in the water. I'm not running a sublimation setup-this is just for normal printing-but now I can't use my ink and I need to get printing again.

Answer: 

Why this happens after a firmware upgrade

On many Epson models (including business/workforce lines), firmware updates can change the "handshake" the printer uses to authenticate cartridges. Most third-party cartridges are manufactured to match a previous handshake method. Once firmware updates tighten the authentication rules, the printer may suddenly display "cartridge not recognized" behavior-even if those same cartridges worked perfectly before.

Unfortunately, in a lot of cases, once the firmware has been upgraded, the printer will refuse older third-party chips unless:

• you use an updated third-party chip set that matches the new firmware, or

• you successfully roll the firmware back (which is often blocked), or

• you repair/replace the memory contents at the hardware level (advanced).

Any error codes?

You didn't mention any specific on-screen error codes (for example, numeric codes or a specific Epson "cartridge error" code). If the printer is simply saying cartridges are not recognized, that's still consistent with a firmware-based lockout-even without a formal code.

What to try first (least risky)

1) Confirm it's truly a chip/authentication problem (quick checks)

These steps won't "fix" a firmware lock, but they help rule out simple causes that mimic a lockout:

• Power the printer off, unplug it for 60 seconds, then power back on.

• Remove and reseat all cartridges firmly.

• Check if the printer recognizes any cartridge as valid (even one). If none are recognized, it can also indicate contact contamination, bent pins, or a carriage board issue-not just firmware.

2) Try a different cartridge chip set designed for the newer firmware

If you can source third-party cartridges (or chip resetters) explicitly labeled as compatible with the current firmware version, that's often the most practical "non-invasive" fix. Many suppliers eventually release updated chips after Epson pushes updates.

3) Disable future firmware updates (so it doesn't get worse)

Once you recover printing, it's wise to prevent repeat lockouts:

• Turn off automatic updates in the printer settings (if available).

• Avoid allowing update prompts through Epson utilities on your computer.

Software rollback attempt (may or may not work)

You're correct that software methods should be attempted first, as long as the printer still communicates over USB.

4) Attempt firmware rollback or recovery using a utility (best-case scenario)

Tools such as WICReset sometimes help in certain scenarios-either by rolling firmware back, repairing corrupted regions, or bypassing a "bad section" that prevents normal operation. I want to be transparent: I have not personally performed this on a WF-7840, and Epson often blocks downgrades on many models. Still, if the printer is talking to the computer, it can be worth trying software approaches first because the risk and effort are lower than hardware intervention.

If the software route works, it may restore compatibility with the older third-party chip style. If it doesn't, it at least tells you the printer's firmware protection is doing its job (which is common).

Hardware recovery (advanced, last resort)

If the printer no longer talks to the computer at all, or if you need a deeper repair path, then you're in "hardware approach" territory.

5) EEPROM programmer method (read/write memory directly)

This approach uses an EEPROM programmer to read and write the memory contents directly on the board:

• You connect a programmer to the EEPROM chip.

• You read a clean binary dump from a healthy donor printer of the same model.

• You write that known-good data back onto the target printer's EEPROM.

A ready-made EEPROM programmer option similar to what you referenced is here: EEPROM programmer example (https://amzn.to/43HA5nw).

Important reality check:
Even with the right programmer, this process can be very technical. Also, firmware locks are sometimes stored across multiple regions or chips, and some models use protections that make a simple write-back ineffective.

6) Replacing the EEPROM chip (sometimes more reliable than rewriting)

If you're already going to the trouble of accessing and programming the EEPROM, it may be wise to replace the EEPROM chip entirely during the process. When printers start acting "corrupt" or unstable, it can be due to wear or degradation in the chip itself. A fresh EEPROM can provide better long-term reliability-assuming you have correct data and the printer model supports this kind of recovery.

The practical takeaway

• If your WF-7840 still connects by USB and operates normally except for rejecting third-party cartridges, the most realistic fixes are either:

  1. updated third-party chips/carts made for the new firmware, or

  2. a software rollback/recovery attempt, understanding it often fails due to Epson protections.

• If the printer won't communicate or is bricked, then only hardware-level repair is left-and that's an advanced electronics workflow.

Addressing printer issues can be a complicated affair because these problems are hands-on-chip authentication, firmware protections, and board-level memory work can't be reliably diagnosed or guided remotely. Because of that, we're not able to provide remote troubleshooting, suggestions, or support for printer repairs. We do offer an in-person evaluation and repair service through our local diagnostic facility: Printer Repair Service (https://bchtechnologies.com/printer-repair-service). Due to high demand, we handle units on a first-come, first-served basis, and it may take a few weeks before you can drop the printer off. Our services are structured to repair either an entire printer or specific parts, with clear instructions on how to proceed. We also recognize our rates aren't the most economical, so we strongly encourage self-help via online research whenever possible. You can start with YouTube or our channel homepage at BCH Technologies on YouTube (https://youtube.com/@bchtechnologies). To find specific topics, use the search icon next to "About" on the right-hand side of the menu bar. I receive dozens of questions every day asking whether we have a video for a particular issue, and after nine years of making videos, it's difficult to remember every single one-YouTube search is the fastest method. Plus, YouTube may recommend helpful videos from other channels that match your exact situation.

Thank you again for reaching out and for supporting BCH Technologies. I hope the steps above help you quickly determine whether you're dealing with a firmware-based cartridge lockout (most common) or a deeper communication/board issue-and point you toward the safest next move.