@petero Hi PeterO, Sorry I didn't get a chance to look into that further - was busy with github stuff etc. Glad you found the problem. These things can be very particular !! Also glad the link was useful....... the SAM menu is fantastic.... with the included I2C scanner and other features. There are also two other excellent menu systems... You can easily add your own apps to the "M5Stack-SD-Updater" menu (more are being added over time) and the other "M5Stack_MultiApp _Firmware" has a number of useful tools included.... including I2C scanner, voltmeter, etc..... https://github.com/PartsandCircuits Enjoy !