User:ManiacOfHomebrew/3DS 12-hour Clock

The 3DS uses the 24-hour time format to display the time on the HOME menu among other applets. This guide shows you how to convert the 3DS system's clock on the HUD of the Home Menu to a 12-hour format. This will not affect other applets such as System Settings or the Nintendo eShop at the moment.

This guide is based heavily on a custom HOME menu guide by Dungeonfire available here.

Create/update your NAND backup! When making changes to your device, there is always the chance you will brick.

Having a custom Home Menu installed breaks system updates. If you want to update your system, you will have to restore your Home Menu with a blank HomeMenu.cia first.

What You Need

The latest version of Home Menu Rebuilding Tool by DeKay
The latest version of MSBT Editor Reloaded
The latest version of GodMode9 installed
Windows - required for this guide currently, may not be in the future

Section I - Preparations

Extract Home Menu Rebuilding Tool as well as MSBT Editor Reloaded to a new folder on your computer
Press and hold Start, and while holding Start, power on your console. This will launch GodMode9
Press HOME to bring up the action menu
Select "Title manager"
Select "[1:] NAND / TWL"
Scroll down through the list and select a title labeled (CTR-N-HMME). This is the Home Menu application
Select "Manage Title..."
Select "Build CIA (standard)"
Push A once it is finished
Push R+Start to power off the console
Insert the SD Card into your computer
Backup the .cia file in the gm9/out folder to a safe place on your computer. It ends with (CTR-N-HMME).standard.cia
Make another copy of this .cia file in the folder created in step 1
Rename it to HomeMenu.cia

Section II - Modifying

Open Home Menu Rebuilding Tool.bat
Push 8 on your keyboard
Wait for it to finish, do not push any buttons. It should open a folder named ExtractedRomFS in a new window
Keep the window open and open MsbtEditor.exe
Drag the file named hud_msbt.LZ from ExtractedRomFS/message_hud/US_English into MsbtEditor
Scroll down and select lau_hours in the list on the left
Change %H to %h in the first text box labeled "Edit:"
Push Ctrl+S to save, then close MsbtEditor
Go back to Home Menu Rebuilding Tool (the window you were instructed not to close) and push any key
- If you accidentally closed it, reopen it, then push 6 then 2 then 3

Section III - Installing

Copy the outputted HomeMenu_edited.cia file to the root of the SD card
Press and hold Start, and while holding Start, power on your console. This will launch GodMode9
Navigate to the [0:] SDCARD drive, then select the HomeMenu_edited.cia file
Select "CIA Image options..."
Select "Encrypt file (...)"
Select "Encrypt inplace"
After it is finished, push A to continue
Select the HomeMenu_edited.cia file again
Select "CIA Image options..."
Select "Install game image"
Press A to unlock SysNAND (lvl1) writing, then input the key combo given
Push A twice then Start to reboot

If all has gone well, you should now see a 12-hour clock on the HUD of the HOME menu. If the HOME menu does not boot or you encounter any other problem, it is recommended that you ask for help on the Nintendo Homebrew Discord server in one of the 3DS assistance channels. You could also ping me, the person who wrote this guide (Username: _themaniac on Discord), there and I will assist you if possible.