PICSimLab Linux Install Problems: .deb Dependencies, Flatpak and AppImage

PICSimLab v0.9.3 gives Linux users three routes — a .deb package, a Flatpak, and an AppImage — and each fails in its own characteristic way: dependency errors from the .deb, a double-click that does nothing from the AppImage, or an installed program that cannot reach serial devices. This page untangles which route you are on and fixes that route’s problem. (For the clean install sequence itself, see our Ubuntu & Debian installation guide.)

Symptoms

  • The .deb refuses to install, ending in unmet-dependency errors.
  • The AppImage does not start on double-click — nothing appears at all.
  • The Flatpak bundle will not install, or PICSimLab is nowhere to be found afterwards.
  • PICSimLab installed and runs, but serial devices (/dev/tnt*) cannot be opened.
  • The NOGUI AppImage “does nothing” — no window ever appears.

Why it happens

There are two different .deb files, and they are release-specific. The project publishes one build for Ubuntu 24.04 (PICSimLab_0.9.3_260920_Ubuntu_24.04.5_LTS_amd64.deb) and a separate one for Ubuntu 22.04 (PICSimLab_0.9.3_260920_Ubuntu_22.04.5_LTS_amd64.deb). Installing the 24.04 package on a 22.04 system (or the reverse) is the most common source of dependency errors — the package is being asked to fit a system it was not built for. A second, general package-management point: installing a .deb with a low-level tool alone does not fetch missing dependencies; installing the same file through apt does.

AppImages need the execute permission — and sometimes FUSE. This is general AppImage knowledge, not PICSimLab-specific: a downloaded AppImage is not executable until you set the execute bit, so a double-click silently does nothing. Some systems also lack the FUSE runtime AppImages use to mount themselves, in which case the file is executable but still will not start from the desktop; running it from a terminal shows the actual error message either way.

Serial devices are permission-gated. PICSimLab’s Linux serial support uses tty0tty virtual devices (/dev/tnt2 <=> /dev/tnt3 etc.). Like real serial devices, those files are owned with restricted permissions; if your user account cannot read and write them, the program cannot open the port no matter how correct everything else is.

The NOGUI build has no window by design. PICSimLab_NOGUI-0.9.3_260920_Ubuntu_22.04.5_LTS_x86_64.AppImage is a terminal-only build — per the official release notes it must be used on a terminal together with the remote control interface (rcontrol, default TCP port 5000). Starting it and waiting for a GUI is a category error, not a crash.

Fix

  1. Match the .deb to your release. Check your Ubuntu version (lsb_release -a in a terminal — general system knowledge) and download the matching package from our PICSimLab for Linux page: the 24.04 .deb (SHA-256 89510e3d917fa9cb19c8dde5b2facdbd0ee4a50422ba3ba487b201c6f2046fa7) or the 22.04 .deb (SHA-256 1862c3e78e99d427b854083d7ce1ab4a3e86023348150bdb695bc381f72921f1). Verify with sha256sum before installing.
  2. Install the .deb through apt so dependencies resolve: sudo apt install ./PICSimLab_0.9.3_260920_Ubuntu_24.04.5_LTS_amd64.deb (adjust the file name to your build). apt pulls the libraries the package needs; a bare dpkg -i does not.
  3. On a non-Ubuntu or mismatched system, switch routes instead of fighting dependencies. The Flatpak (picsimlab_Linux_0.9.3_260920.flatpak) installs with flatpak install picsimlab_Linux_0.9.3_260920.flatpak and is the comfortable route off the two supported Ubuntu releases; the AppImage needs no installation at all. The simulator in all three is the same program.
  4. Fix the AppImage launch. Run chmod +x PICSimLab-0.9.3_260920_Ubuntu_22.04.5_LTS_x86_64.AppImage, then start it from a terminal (./PICSimLab-0.9.3_260920_Ubuntu_22.04.5_LTS_x86_64.AppImage) so any error is visible. If the terminal points at FUSE, install your distribution’s FUSE package (general AppImage requirement) and retry — or fall back to the Flatpak route.
  5. Fix serial device access. After installing tty0tty, make sure your user can read and write the /dev/tnt* devices it creates: check the device permissions, add your account to the group that owns serial devices if needed (on mainstream distributions serial devices are conventionally group-gated), then log out and back in so group changes take effect, and test again. Our virtual serial ports guide covers the pair setup itself.
  6. For the NOGUI build, drive it from the terminal. Start the NOGUI AppImage in a terminal and control it through rcontrol (connect to port 5000 with telnet or nc and use its text commands, e.g. to load a .hex and start the simulation). If you wanted a window, install one of the GUI builds instead — there is no Windows or macOS NOGUI build; it exists only as this Linux AppImage.

Still stuck?

Work through the Ubuntu & Debian installation guide route by route, with the file table on the Linux download page open beside it. If the release-matched .deb installed through apt — or the Flatpak — still will not run on v0.9.3, report it with your distribution and release, the route you used, and the terminal error text, on the project’s tracker: github.com/lcgamboa/picsimlab/issues.

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