It is possible that the filesystem is, in fact, full. What is the file size of the “embedded_kit_gateway.zip” file? Do you know what other files are loaded in the filesystem for Python?
There are two possible limits that are being reached, RAM and flash.
First, can you determine how much system RAM is free when you attempt the upload operation? This can be seen in the “System Information” selection in the web interface. This is not the most likely candidate, but worth testing.
Second, the .zip file size may be pushing the size limit of the filesystem available to Python. The effective size of the filesystem is just over 830k. Filesystem overhead might push your observed total bytes to be stored over the internal limit. Are you able, for instance, to upload a “.zip” file 50% or even 75% the size of “embedded_kit_gateway.zip”?
The intention is to determine whether this is a true limitation, or an error.