"PS4 error code SU-42481-9" might have encountered a problem when updating the firmware. A power cycle might able to help to fix the problem. To power cycle PS4, turn off the console and unplug it for at least 30 seconds and then turn it on.
Try to update it first using the PS4 System Software Update.
If the error still exists use the Safe mode Update System software.
2. Safe Mode Rebuild Database
If the error “PS4 error code SU-42481-9” still arise the problem could be the firmware. It could be corrupt. Try to Rebuild the database to verify the integrity of the firmware. See it here on a YouTube video to access Safe mode or see instructions below.
Scroll down and look for “Perform a new installation of the system software.”
Click to expand.
Next click “DOWNLOAD NOW” to download your firmware.
Step 2. Create a Folder inside the USB flash drive
Create a folder named it as PS4 (case sensitive).
Then open it, and then create a folder name UPDATE (case sensitive).
Then copy the downloaded file and paste it inside the UPDATE folder and name it as PS4UPDATE.PUP(case sensitive).
Next do a power cycle to your PS4 by, turning it off and then unplug it for at least three minutes.
Next turn it on and then flash your PS4 by accessing PS4 Safe mode.
4. Initialize PS4
If the “PS4 error code SU-42481-9” continues you may want to restore your console to factory default settings using Initialize PS4 in Safe mode. Warning it some file or all files might be deleted on this process. Please back up your save files and other data. To Initialize PS4, using the instruction in solution 2 to access Safe mode select number "6. Initialize PS4" and if it doesn't work select number "7. Initialize PS4 (Reinstall System Software)."