To install Cydia on iOS8-8.1 manually.
1. Install OpenSSH in pangu application.
2. Download those two debs on your computer.
http://apt.saurik.com/debs/cydia-lproj_1.1.12_iphoneos-arm.deb
http://apt.saurik.com/debs/cydia_1.1.13_iphoneos-arm.deb
3. Then enter SSH over USB.
4. Open a new terminal, and scp the two debs download just now to your device. (assuming you are using port 25252 in step 3)
scp -P 25252 cydia-lproj_1.1.12_iphoneos-arm.deb cydia_1.1.13_iphoneos-arm.deb [email protected]:/var/mobile/
5. Back to SSH. Then execute those commands:
cd /var/mobile/
dpkg -i cydia-lproj_1.1.12_iphoneos-arm.deb cydia_1.1.13_iphoneos-arm.deb
killall -9 SpringBoard
6. If Cydia icon doesn't show on your springboard, you can do those to solve the problem(in SSH)
cd /Applications
mv pangu.app jail.app
mv Cydia.app pangu.app
killall -9 SpringBoard
Then touch pangu icon on springboard, you should see Cydia is preparing filesystem.