: Cert signature or hash check failed (106) — The file's internal integrity checksum does not match what the 3DS expects. Step 1: Fix Network and CIA File Corruption
This error usually points to a corrupted download, a bad CIA dump, an issue with your SD card, or an incorrect developer setting in your custom firmware.
If the cryptographic signature failed, the file itself is likely missing pieces. failed to install cia file 0xd8e0806a updated
Turn off your 3DS and insert the SD card into your computer.
An update CIA cannot install if the base game is missing or from a different region. : Cert signature or hash check failed (106)
the CIA file you are trying to install is corrupted, incomplete, or incorrectly signed for your system Primary Fixes Re-download the CIA File
Use a tool like H2testw (Windows) or F3 (Mac/Linux) to scan your SD card. Turn off your 3DS and insert the SD card into your computer
The search results include various sources:
Check your SD card space in the 3DS System Settings or by plugging the card into a computer. Clean up space if you are running low. 3. Check for SD Card Corruption