Third-party status
UnknownNon-Epson cartridges blocked after updates; no firmware number confirmed
Risky. Epson says non-Epson 812 cartridges that worked may stop after a firmware update, and WF-7840 owners have reported exactly that since 2022. No source we trust names the firmware version, so the status stays Unknown.
What to do now
- Turn off automatic firmware updates while third-party cartridges work, and update only with genuine cartridges installed, as an owner suggested in January 2024.[4][1]We have not verified the menu path to turn off automatic updates on this model.
- Some owners report restoring third-party cartridges by reflashing an older firmware in recovery mode.[4][8]Others report the downgrade failing or the cartridges still not being recognized; a failed flash can leave the printer unusable. Epson does not support this.
What to buy instead
- Genuine Epson 812 / 812XL. Always recognized, and the 812XXL black is the cheapest genuine option per page.
- Compatible 812XL with a firmware return policy. Ask what happens if an update rejects them.
- Account required
- No
- Cartridges
- Epson 812 / 812XL / 812XXL (black) cartridges
- Blocking firmware
- None reported
- Last checked
Also applies to: WorkForce Pro WF-7820, WF-7310 and WorkForce EC-C7000, which Epson lists for the same 812 cartridges (check your cartridge number).
Third-party and remanufactured cartridges
- Epson's WF-7820/WF-7840 FAQ says the printer is designed to work only with genuine Epson cartridges, that firmware updates may affect third-party ink, and that non-Epson or altered cartridges that worked before an update may not continue to work.[1]
- Epson's 'ink not recognized after a firmware update' FAQ for the WF-7840 tells owners to replace non-Epson cartridges with genuine Epson ones.[2]
- Epson lists 812, 812XL and 812XXL (black) cartridges for the WF-7840, the same cartridges as the WF-7820, WF-7310 and EC-C7000.[3]
- Owner reports: a WF-7840 owner posted on January 13, 2022 that non-Epson cartridges stopped being recognized two days after a firmware update; others posted similar reports in July 2022 and July 2023.[4][5][6]
Epson account and subscriptions
- Epson's setup sheet says the printer sends its serial number to an Epson server during setup so you can be eligible for programs such as ink replenishment, with a separate chance to consent. We found no requirement for an account or subscription to print.[7]
Firmware that blocked cartridges
- No Epson source we found names the WF-7840 firmware version that changed cartridge checks.[1][2]
- An iFixit question names firmware CD17M6 as the version on which the poster's non-Epson cartridges stopped working, and CD08M4 as an older version others reflashed. These are owner claims, not Epson statements, and the thread is undated in what we could read.[8]
To see your version, print a printer status report or open the printer's web page. Compare it with the firmware list.
Workarounds that sources back up
- Turn off automatic firmware updates while third-party cartridges work, and update only with genuine cartridges installed, as an owner suggested in January 2024.[4][1] We have not verified the menu path to turn off automatic updates on this model.
- Some owners report restoring third-party cartridges by reflashing an older firmware in recovery mode.[4][8] Others report the downgrade failing or the cartridges still not being recognized; a failed flash can leave the printer unusable. Epson does not support this.
What does not reliably work
- Asking Epson support to roll back: the January 2022 poster said an Epson specialist told them the update could not be rolled back and they had to use Epson ink.[4]
- Downgrading is not reliable: one owner reports the flash failing outright, and an iFixit reply reports cartridges still unrecognized after reflashing.[9][8]
What to buy instead
- Genuine Epson 812 / 812XL. Always recognized, and the 812XXL black is the cheapest genuine option per page. Shop
- Compatible 812XL with a firmware return policy. Ask what happens if an update rejects them. Shop
These are plain store links. We earn nothing from them today. Disclosure.
What we could not verify
- The firmware version, if any, Epson used to block third-party cartridges on the WF-7840 (owner posts mention CD17M6, unconfirmed).
- Any WF-7840 owner report from 2026; we found no live complaints on X this week.
- Whether the firmware downgrade still works on current firmware.
- The menu path to turn off automatic updates on this model.
Know something we missed? Dated sources beat opinions. Corrections go on the page with a date.
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Sources
- Epson FAQ: WF-7820/WF-7840 replacing ink cartridges (firmware warning) (published Oct 1, 2020)
- Epson FAQ (WF-7840): after a firmware update the ink is not recognized (read Nov 9, 2026)
- Epson Ink Finder: WorkForce Pro WF-7840 (read Nov 9, 2026)
- r/Epson: WF-7840 firmware update, ink cartridges no longer recognized (published Jan 13, 2022)
- r/Epson: owner reports third-party ink disabled after update (WF-7840 reply) (published Jul 29, 2022)
- r/Epson: WF-7840 cartridges won't work due to update (published Jul 12, 2023)
- Epson: WF-7820/WF-7840 Start Here setup sheet (PDF) (read Nov 9, 2026)
- iFixit Answers: problem downgrading the firmware of an Epson WF-7840 (read Nov 9, 2026)
- r/printers: trying to downgrade Epson 7840 firmware, failed to flash (read Nov 9, 2026)