Installing JESSI on iOS 17.4‐18.7.9

To install JESSI on iOS 17.4-18.7.5, we will first install SideStore, and then we will install StikDebug (to enable JIT) and JESSI inside of SideStore. Installing SideStore requires a computer, but after this initial setup you will no longer need a PC. If you already have SideStore and StikDebug installed, skip to Installing JESSI and enabling JIT.

Installing SideStore

1. On your computer, download and install the latest release of iloader for your platform. If you are on Linux, you must install usbmuxd (this comes preinstalled on most distros). If you are on Windows, you must install iTunes, NOT from the Microsoft store
2. Plug your idevice into your computer, and trust your computer on your idevice
3. Open iloader and ensure that your idevice is detected (should show on the right side)
4. Log in with your Apple ID on the left (This will only be sent to the Apple servers)
5. Make sure the correct idevice is selected, then in the installers section click SideStore (Stable) and wait for it to install (you must have a passcode on your idevice, otherwise placing the pairing file will fail)
6. On your idevice, open the App Store and install LocalDevVPN
7. Open the LocalDevVPN app, skip the popups, then tap the "Connect" button. This will take you to the Settings app, and ask you to allow LocalDevVPN to add VPN configurations. Accept this and enter your passcode
8. Open the Settings app, then go to Privacy & Security > Developer Mode and toggle on Developer Mode
9. Tap on the restart button when it pops up, then wait for your phone to reboot
10. Unlock your idevice and tap the turn on button, then enter your passcode
11. Open the Settings app, then go to General > VPN & Device Management and tap on the profile with your Apple ID
12. Trust the profile, enter your passcode if it requests you to do so
13. Open the SideStore app, and go to the "My Apps" tab, and tap refresh. Log in with your Apple ID when prompted
14. SideStore is now set up and ready!

Installing StikDebug

In order to enable JIT inside of JESSI, you will need to install StikDebug and use that to enable JIT. Before following this section of the guide, make sure you are connected to wifi, cellular data, or you have airplane mode turned on and connect to the LocalDevVPN VPN.

1. On your idevice, download the latest release of StikDebug
2. Open the SideStore app, go to the "My Apps" tab, and tap the plus button
3. In the file picker, navigate to the StikDebug ipa you just downloaded, then tap on it to start sideloading it
4. When it gives you a popup, select "Keep app extensions - use main profile"
5. After StikDebug finishes installing, plug your idevice into your computer and trust your computer on your idevice
6. On your computer, open iloader and click the "Manage Pairing File" button
7. In the StikDebug row, click the "Place" button to place your idevices pairing file inside of StikDebug
8. StikDebug is now set up and ready!

Installing JESSI and enabling JIT

Before following this section of the guide, make sure you are connected to wifi, cellular data, or you have airplane mode turned on and connect to the LocalDevVPN VPN.

1. On your idevice, download the latest release of JESSI
2. Open the SideStore app, go to the "My Apps" tab, and tap the plus button
3. In the file picker, navigate to the JESSI ipa you just downloaded, then tap on it to start sideloading it
4. When it gives you a popup, select "Keep app extensions - use main profile"
5. After JESSI finishes installing, open StikDebug
6. Tap the "Enable JIT" button, then select JESSI (if it doesn't immediately open JESSI, wait a few seconds and try again)
7. JESSI is now installed and JIT is enabled! If you close JESSI and need to re-enable JIT, just repeat step 6

In the System section of the settings tab, JESSI will tell you if JIT is enabled or not. If it is not enabled, you won't be able to start a server or create a forge/neoforge server.