Tag Archives: tips

How to fix permission denied flashing Prusa Firmware on Arch Linux

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I ran into a permissions issue flashing an update to my 3D printer “Prusa MK3S+” on Arch Linux and the fix was easier than expected.

For background, this is my first time doing this so I wasn’t too sure about the procedure, the printer beeped before print to let me know there’s newer firmware available and I should upgrade. I checked online and found these instructions on the Prusa help site for how to flash firmware. It seems easy enough:

  1. Connect the printer to the laptop with USB
  2. Go to Menu → Configuration → Flash printer firmware
  3. choose the .hex file you downloaded from the Prusa website

that’s it!

However, when I clicked the “Flash!” button I got the following error message from the flasher’s log output:

avrdude-slic3r: ser_open(): can't open device "/dev/ttyACM0": Permission denied
avrdude-slic3r: Could not open port: /dev/ttyACM0

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3D-printed caps for protruding bolts

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When I attached our children’s swing to the ground there was still a significant piece of sharp-ish threaded metal sticking out above the bolt head and I was worried about them falling on it. Grinding the end off might still leave some sharp parts, so I thought it safer to print plastic covers for them.

Sharp bolt end protruding from the ground
Screenshot of bolt cap design in OpenSCAD
Screenshot of gcode printing plan
Photo of 3D printed bolt cap

I designed the caps with OpenSCAD, using the ScrewsMetric library for the bolt-shaped inset.

You can see the source code for Continue reading →

Use HOME as your GOPATH

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How and why I normalised my Go paths and personal/local home paths.

Like many people, I have my own scripts and stuff in a bin directory in my home directory. Actually it’s a symlink to ~/.local/bin because I saw there was a ~/.local/share which some programs use to store user-specific things and I wanted to be consistent.

Then I saw some people have ~/bin and ~/src and I thought that looked like a Continue reading →

Rooting Samsung Galaxy Mini

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Samsung Galaxy Mini

Samsung Galaxy Mini

My wife’s phone (Samsung Galaxy Mini GT-S5570I) doesn’t get system updates any more, so I need to manually move Google’s updates into ROM to make space for regular apps. You need root privileges to do this, so I was following these instructions on the XDA Forum which almost work fine. You need to download and apply a file update.zip but the problem is the update script inside doesn’t include S5570I in the list of phone models it checks for, so the script aborts.

All you need to do is edit /META-INF/com/google/android/updater-script inside update.zip and include this phone model in the assertion list, for example, I duplicated lines 15 and 16 and just added an I to the end:

getprop("ro.product.device") == "GT-S5570" ||
getprop("ro.build.product") == "GT-S5570"  ||
getprop("ro.product.device") == "GT-S5570I" ||
getprop("ro.build.product") == "GT-S5570I"  ||

Everything works completely fine after that. Obviously this is not a general solution when rooting, you can’t just blindly add your own phone model into any update.zip not knowing what’s in it, but since this was from a post for specifically this model and it already had several very similar models listed, I thought it was worth the risk and it turned out just fine. Woop! 😎

grml zsh inPlaceMkdirs

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I keep forgetting this, but it’s really useful when working in the command line so I’m writing it down now. I use the grml zsh configuration in my shell and it has several very good features; a cool one I’d use more often if I could remember the shortcut is “in-place mkdir”. The key sequence is:

Ctrl-X, Shift-M

That’s Ctrl and x, followed by an uppercase M.

Here’s an example use case: Imagine you’re writing a command to do something with a very long path, like moving a file deep into a source tree

mv File.java src/something/very/long/

except half-way in your realise some of the directories in that path don’t exist. No problem! Usually you’d have to cancel that command, create the missing directories and then type it again. Now you can just type Ctrl-X, Shift-M, the directories are created and you can just press enter to use them. Much less annoying! This can even work for different directories in the same command; move the cursor to the directory you need and zsh will create that one!

For other useful shortcuts, see the reference card.