A method implemented by an image recording unit having a normal state and an error state of operation. The method includes: receiving metadata specifying information about a patient and/or an endoscopic procedure; receiving images generated by an image sensor of an endoscope, the images corresponding to optical images received by the image sensor and comprising single images and/or a stream of images; controlling a display to show the images; in response to a first user input in the normal state, storing the images and the metadata in a memory of the image recording unit, and in the error state, overwriting with new data at least some of the metadata.