Flipper Zero

Firmwares

Update to the latest firmware using https://flipperzero.one/update
Download and install qFlipper
Connect your Flipper Zero via USB, update to the official firmware
Disconnect from USB, power off the Flipper Zero, and remove the SD to prepare it for flashing.
Download the latest RogueMaster firmware from their Github Page.
Unzip the downloaded .zip and copy the content into /update of the Flipper SD card (including the .dfu)
On the Flipper Zero, once booted, press down, and left until you are on the 'Browser' screen. Scroll down until you see the 'update' directory and click on it.
You should now see the contents you uploaded and an 'update' option. Hover over the 'update' option, click the center button on your Flipper, once again on the 'Run in App' option.