Hi
If you want to rollback the ribbon to it's original state (i.e. the state of the ribbon as it existed when the entity was first created) you will need to modify the RibbonXML manually by creating solution which only contains the Application Ribbon and your
custom entity. Export the solution as unmanaged and unzip the solution zip file. Open the customizations.xml file and search for RibbonDiffXml. Remove everything inside the <RibbonDiffXml> tag and then save and rezip the file. Import it back into CRM
and publish all customizations.
The ribbon should reset to it's original state.