HP178nw HEADER BUFFER - PORTABLE MENU-BAR APP, VERSION 1.3.0 Built 24 October 2026 USE AT YOUR OWN RISK - NO WARRANTY OR LIABILITY This is an independent, experimental workaround, supplied as is and as available. To the maximum extent permitted by applicable law, the developer accepts no responsibility or liability for claims, damage, costs or losses from installing, using, or being unable to use this software. You accept responsibility for its use and consequences, including printer problems, failed printing, paper or toner waste, data loss and interruption of work. Nothing excludes liability or rights that the law does not allow to be excluded. Read DISCLAIMER.txt for the full notice. Version 1.3.0 adds the opt-in Launch at login menu option on macOS 13 and later. It uses Apple's ServiceManagement framework and displays the system's actual status. It never enables itself at startup, and shows when macOS needs approval. Copy the app to Applications before enabling it. The printer filter is unchanged. Since version 1.2.3, you must choose Agree & Continue on the notice before the normal app can check or change printer settings. Acceptance is saved only on your Mac, for your user account and this notice revision. Declining quits without running a printer helper. An existing queue/filter is not removed by declining; removal and the read-only --check remain available without accepting. You can reopen the notice from the app's menu. Version 1.2.2 fixed the printer chooser when more than one source queue is available. Its result now uses an explicit local variable, avoiding the AppleScript application property named "selection". Choosing either queue and cancelling the chooser are checked through the native launcher with inert printer helpers. Version 1.2.1's resource-path correction is retained. The printing filter and queue behaviour are unchanged. WHAT IT DOES This app packages the initial-raster-header workaround tested on an HP Color Laser MFP 178nw, with a printer icon and an On/Off switch in the Mac menu bar. On another Mac it creates a separate, unshared AirPrint queue using that Mac's existing printer connection and profile. It changes only two URF filter registrations in the copied profile. The filter buffers the first 44 bytes, then forwards the entire raster unchanged. It does not print a test automatically. Your original printer remains available and its scanner configuration is retained. USE ON ANOTHER MAC 1. Copy HP178nw-Header-Buffer.dmg to that Mac, for example using AirDrop, and open it. The disk image contains no captured documents or logs. 2. Add the HP 178nw in System Settings > Printers & Scanners using AirPrint if it is not already added. 3. Drag "HP178nw Header Buffer.app" onto the Applications shortcut, then open the app from Applications. The Support folder in the disk image contains the removal app, this guide, readable sources and the low-toner test PDF. 4. Choose the original HP queue if more than one is listed. Click Install & Use and approve macOS's administrator prompt. The app selects the new "HP 178nw Header Buffer" printer for your account when setup succeeds. 5. Print one copy of low-toner-two-pages.pdf from Preview, explicitly selecting the buffered printer. The menu can also open this PDF. Check that both numbered pages are correct. Cancel at the printer if gibberish starts. The app uses native macOS tools. No Python, Homebrew, compiler, third-party runtime, network download or remote account is needed on the destination Mac. It requires the system Perl runtime and the PPD/CUPS AirPrint filter path; preflight stops without installing if those prerequisites are unavailable. The release apps are signed with a Developer ID Application certificate and use the hardened runtime. macOS checks the signature and Apple notarization when opening downloaded software; the final release disk image carries its notarization ticket. The normal downloaded-app confirmation and the one-time administrator prompt for printer setup may still appear. No security settings need to be disabled. This independent workaround is not an HP product. LOGIN STARTUP Keep HP178nw Header Buffer.app in Applications. On macOS 13 or later, click its printer icon and choose Launch at login. A checkmark means macOS has enabled it; choose it again to turn it off. The option is opt-in, independent of Header buffering On/Off, and is read from macOS rather than a saved guess. If the menu says approval is needed, it offers to open the macOS Login Items settings or turn the registration off. The app does not override a system denial or silently enable itself again. No administrator password is needed for this login-item option. On macOS 11 or 12, the app and printer workaround still work; add the app manually in System Preferences > Users & Groups > Login Items. The built-in Launch at login control requires macOS 13 or later. The app stays in the menu bar, beside the other icons near the battery/clock. Click its printer icon to see the switch: On: select the buffered HP printer as your default for new jobs. Off: return to your original HP printer if the buffered printer is selected. Your On/Off choice is saved and restored the next time the app opens, including at login. Switching leaves jobs already queued/printing on their existing queues. It needs no administrator approval after the one-time setup. The menu shows the current selected printer and refreshes when your user printer defaults change. It does not poll or capture traffic from the printer. The installed filter applies header buffering to each job sent to the buffered queue, including if the menu-bar app has been quit. Quitting closes the icon; use Off before quitting if you want the original printer selected. Other printers can still be selected normally. A print dialog or macOS's "last printer used" setting can choose a different queue later in a session. The workaround applies when the selected queue is the buffered one. On the original investigation Mac, the app recognizes and reuses the verified "HP 178nw Header Buffer Test" installation, avoiding a duplicate queue or a second administrator installation. The first open selects that queue by default; subsequent opens restore your saved On/Off choice. Merely downloading/copying this app changes no setting. REMOVE 1. Turn off Launch at login in the printer-icon menu, then choose Quit. If you added the app manually, remove it from Login Items in System Settings too. 2. Open "Remove HP178nw Header Buffer.app", confirm removal, and approve the administrator prompt. Finish/cancel buffered-queue jobs beforehand. The app restores your original default if the buffered queue was selected, then removes only the buffered queue and its marked helper directory. 3. Delete the two apps if you no longer need them. Removing only the app or only its Login Item does not uninstall the CUPS filter. The companion removal app also recognizes the original investigation test installation. A damaged/unrecognized installation is left in place for inspection rather than overwritten or broadly deleted. MANUAL CHECK / RECOVERY The readable installer and helper scripts are inside the app at: HP178nw Header Buffer.app/Contents/Resources/Payload/ Read-only preflight (adjust the app path if needed): /bin/zsh "/Applications/HP178nw Header Buffer.app/Contents/Resources/Payload/install.zsh" --check If the portable installation exists and must be removed manually, first set your normal user's default to an existing original queue, then run: sudo /bin/zsh /Library/Printers/HP178nwHeaderBuffer/uninstall.zsh For the earlier investigation test installation, the rollback is: lpoptions -d HP_Color_Laser_MFP_178nw sudo /bin/zsh /Library/Printers/HP178nwHeaderTest/rollback.zsh TEST STATUS AND LIMITS The original filter preserved three raster samples byte for byte, and a native two-page Preview job on the investigation Mac printed correctly with exactly the same raster data as an earlier failing job. The earlier controlled matrix also separated two successful complete-header cases from two failing split- header cases. This is evidence for a useful workaround, not a measured long-term reliability guarantee or a firmware fix. The menu and graphical switch were checked in an isolated preview, including On -> Off -> On and matching status labels. Queue-switch tests verify that On/Off preserves active jobs, both queues and the exact filter. First-time GUI installation and physical output still need verification on the other Mac. This portable app is scoped to the HP 178nw and compatible existing AirPrint profiles. It is not a generic fix for other printer models. The MacBook Air's saved profiles are checked offline during development; installation and physical output must still be verified on that Mac. CUPS marks PPD-based drivers as deprecated, so this app does not promise compatibility with a future macOS release that removes that mechanism. SOURCES Apple login items: https://support.apple.com/guide/mac-help/open-items-automatically-when-you-log-in-mh15189/mac CUPS filter interface and file permissions: https://openprinting.github.io/cups/doc/api-filter.html CUPS queue/profile management: https://openprinting.github.io/cups/doc/man-lpadmin.html