I recently received a request to build a BLX-1 battery dummy. After designing and building a prototype, I successfully tested the prototype on an OM-1 at Fotozentrum in Krems (Austria).
As a result of theis test, I am now building BLX-1 battery adapters on request.
I don’t know of a source for spare part OM-1 battery compartment lids. Therefore I can’t provide modified battery compatment lids yet. The dummy is secured by the red notch that also keeps the battery from falling out of the camera. The dummy will stay in place, even when the lid is open or removed.
More info about battery dummies on my Battery-Dummies page.