Here is a clean way to remove parental controls on an unpatched Nintendo Switch
You will need your BIS Key 0
Get Lockpick_RCM and dump your keys
Open prod.keys saved in SD card and take note of "bis_key_00"
You will need to mount your eMMC and get PRODINFO.bin
Get memloader and HacDiskMount from https://switchtools.sshnuke.net/
Place the contents of memloader "sample" folder to root of your SD card
Load memloader.bin and choose ums_emmc.ini
Run HacDiskMount as administrator, click on PRODINFO, enter your BIS Key 0 and dump the PRODINFO.bin file
Get your device ID
Open PRODINFO.bin in a text editor
Locate "NintendoNXCA1Prod1" text
To the right of it, you'll see your device ID in the form of "NX0000000000000000-0"
16 digits between "NX" and "-0" is the ID
Follow the guide "Forgot Parental Controls PIN" on Nintendo support
Generate master key with https://mkey.salthax.org/, enter your device ID
Success!