I am stuck at work, and i tried to install ios 8.4 to my iPhone 5s, now it's stuck on the "Connect to iTunes" screen, well I don't have a computer with iTunes on it. My laptop is my work computer and it's and ASUS, and I can't install iTunes on any of the desktops here because it's not allowed. I desperately need my phone for work right now. I've tried resetting it, locking it, everything.
Same problem happened to iOS6, and iOS7 update, and try the steps in this article. https://support.apple.com/en-us/HT201263
If you don’t have iTunes, take your phone to a computer that does. You can get your settings entered and restore from iCloud backup (if you have one) once ios is restored.
What worked for me after crawling around the internet was to install the latest version of iTunes then running it in Administrator mode. Meaning right clicking the iTunes program and click on "Run as Administrator."
What gave me the idea was after running a diagnostic test, it mentioned "User is not an administrator." So I said, hmmm maybe this is what is causing this. That did it and it worked and now my phone is updating and out of recovery mode.