If your firmware download is stuck or failing, try these quick fixes:
If the OS is corrupted, hold the Volume Up and Volume Down buttons while powering on the console to enter Maintenance Mode and attempt a "System Update without Deleting Save Data." Summary Checklist download firmware nintendo switch
The operating system (OS) of the console itself. If your firmware download is stuck or failing,
Always keep a stable Wi-Fi connection during the process. download firmware nintendo switch