FAQ items specific to the Marlin firmware.
I cannot select files on the printer's SD card
There existed a bug in Marlin that truncated the last character of commands sent to it for M23 (select file), M28 and M928 (start writing to file), M30 (delete file), M32 (select file and start printing it) and M117 (display message on printer's LCD) under certain conditions. In the case of the SD card handling commands, that leads to truncating the last character of the file's name, thus leading to problems further down the road (the file not being found etc).
Please make sure your version of Marlin includes this commit that fixes the truncation or at least replicates it. If you don't compile your firmware yourself, please urge whoever is maintaining it for you (the vendor of your 3D printer or someone else) to make sure that fix is included in it.
I cannot select and start printing files on the printer's SD card
Please refer to "I cannot select files on the printer's SD card" above, this is caused by the same issue.
I cannot write to files on the printer's SD card
Please refer to "I cannot select files on the printer's SD card" above, this is caused by the same issue.
When I delete a file from the printer's SD card, the communication stalls
There existed a bug in Marlin that caused the acknowledgement for the deletion of a file on the SD card to be formatted wrong (according to the common protocol -- the ok that finalizes the command processing was not on a different line but directly concatenated with the File deleted:<filename> message), making the mandatory ok look like it was part of the deleted file's name.
Please make sure your version of Marlin includes this commit which fixes the format of the acknowledgement or at least replicates it. If you don't compile your firmware yourself, please urge whoever is maintaining it for you (the vendor of your 3D printer or someone else) to make sure that fix is included in it.
Messages I sent to the printer via M117 are truncated
Please refer to "I cannot select files on the printer's SD card" above, this is caused by the same issue.
I have my printer set to a language that is not english and OctoPrint doesn't work properly
The communication between hosts (e.g. OctoPrint) and printer firmware (e.g. Marlin) underlies a agreed upon protocol, readable by humans and machines, in english language. Marlin used to contain code that sadly also translated the protocol messages into the selected display language (e.g. German, Spanish, Italian, ...).
Please make sure your version of Marlin includes this commit that returns the protocol messages back to english-only or at least replicates it. If you don't compile your firmware yourself, please urge whoever is maintaining it for you (the vendor of your 3D printer or someone else) to make sure that fix is included in it.