Minecrift+Forge+Linux

minecrift.txt

Required files:

Minecraft.jar
forge-1.7.10-10.13.4.1448-1.7.10-installer.jar
minecrift-1.7.10-R1c-installer.jar

Steps:

1. Run Minecraft launcher: java -jar Minecraft.jar
   Edit the profile and select 1.7.10. Launch the game and then exit.
   This creates the 1.7.10 profile info in ~/.minecraft/versions/1.7.10 
   and downloads the jars to ~/.minecraft/libraries/
   Ensure that you have the directory ~/.minecraft/versions/1.7.10 after this
   step.

2. Install forge: java -jar forge-1.7.10-10.13.4.1448-1.7.10-installer.jar
   Select "Install Client". This downlods more jars in ~/.minecraft/libraries/
   and creates profile ~/.minecraft/versions/1.7.10-Forge10.13.4.1448-1.7.10

3. Test forge works. Run Minecraft launcher and edit the profile. Select
   1.7.10-Forge10.13.4.1448-1.7.10 and make sure it runs. You will see
   the forge version on the title screen in the bottom left.

4. Install Minecrift: java -jar minecrift-1.7.10-R1c-installer.jar
   "Add Minecrift launcher profile" should be selected. Don't select anything
   else yet. The installer may display an error at the end, but it should
   still work. You should have ~/.minecraft/versions/minecrift-1.7.10-R1c-nohydra
   after this step.

5. Test Minecrift: Open Minecraft launcher, edit profile and select 
   minecrift-1.7.10-R1c-nohydra then run the game. You should see the typical
   side-by-side 3D view and you should see Minecrift on the title screen in the
   bottom left.

   --- If Minecrift doesn't work or is missing at this stage try repeating step 4. ---

6. Install Minecrift+Forge. Repeat step 4 but this time DO select forge support.
   This should create ~/.minecraft/versions/minecrift-1.7.10-R1c-forge-nohydra

7. Run Minecraft launcher and edit profile. 
   Select minecrift-1.7.10-R1c-forge-nohydra profile and test it. It probably
   won't work. Edit the profile again and at the bottom tick "VM Arguments" and
   delete the contents of the box next to it. The put in the following line in
   the box:

   -Xmx1G -Dfml.ignoreInvalidMinecraftCertificates=true -Dfml.ignorePatchDiscrepancies=true

   Now run this profile again and it should now load to the title screen.
   You should see the side-by-side view and in the bottom left both forge and
   minecrift should appear.

8. Install FTB mods into your custom Minecraft setup:
   Go to ~/ftb/FTBInfinity/minecraft/mods/ and copy everything from there into
   ~/.minecraft/mods/

   Unfortunately this doesn't work: some mods are just not compatible with
   Minecrift and it will just crash back to the title screen when you try to
   enter the world. However, at least some mods DO work. I tested with
   BiomesOPlenty and it worked correctly, for at least a few minutes.

   You will need to test each mod to see if it works correctly.