Always ensure you have backups before performing a reset. These processes erase all data on your device.
If you're looking for instructions specific to a Nokia model (e.g., Nokia 2.4, Nokia 5.4, etc.), providing the exact model could help tailor the instructions more accurately. qm215 emmc nokia hard reset upd
If you're experiencing issues specifically related to the eMMC storage (like constant write failures or similar), a factory reset might not directly solve hardware-specific problems. In such rare cases, professional service might be required. Always ensure you have backups before performing a reset