FAQ items specific to "Original Prusa" printers.
If you are running firmware 3.1.0 to 3.1.1 RC4 please continue reading below since those firmware versions are known to cause severe serial communication issues thanks to the Linear Advance feature being enabled. For earlier firmware versions read on.
It looks like the Prusa firmware up until 3.1.1 RC5 has a bug that causes resend requests to (sometimes?) be sent without the needed
ok, causing OctoPrint to stall since it doesn't get a signal from the firmware to proceed with sending lines to it.
OctoPrint 1.3.7 and up will detect this and work around it. In older versions you could set a flag to "always simulate an
ok after a resend request", but since this specific firmware issue isn't showing itself consistently, that could introduce additional issues leading to further communication issues.
This is a known issue at least with firmware 3.1.0 through 3.1.1 RC4 on the MK3 and also 3.1.0 on MK2/MK2s. Apparently the "Linear Advance" feature causes severe issues in general serial communication due to timing and overload issues.
For MK2/MK2s downgrade to 3.0.12 (without Linear Advance) until a fixed build is available.
For MK3 make sure to use 3.1.1-RC5 or later (also without Linear Advance) which is supposed to fix this.