Meshtastic uses the [littlefs](https://github.com/littlefs-project/littlefs) library to store configuration, logs, and other data in the internal flash of nRF52 & RP2040 devices. Updating the firmware does _not_ erase this additional data, which can cause issues when the format and location of data changes between releases.
You may now use the [Meshtastic Web Flasher](https://flasher.meshtastic.org) to Factory Erase your nRF52 or RP2040-based devices. Visit the flasher, select your board, and click the trash can icon to the right of the Flash button. This will open a dialogue to begin the erase procedure.
7. Find the file included in the downloaded firmware matching your softdevice major version number (7.x.x or 6.x.x). Either use `Meshtastic_nRF52_factory_erase_v3_S140_7.3.0.uf2` or `Meshtastic_nRF52_factory_erase_v3_S140_6.3.0.uf2` and copy it onto the new drive. The device should reboot.
8. With the [Meshtastic CLI](/docs/software/python/cli/) installed, open your Terminal/Console and enter the command: `meshtastic --noproto`.
9. You should see the message: `Formatting... Done`.