I tried creating a new profile - didn't work, creating a new version - didn't work, and doing a different version - didn't work. I'm trying to install forge on the old release 1.2.5 but the .jar keeps resetting on startup
That's because the edited jar fails the checksum for being the wrong size, so it is considered invalid by the launcher and the launcher re-downloads it. as far as I know, the only way past that is to launch in offline mode.
[EDIT] you might also be able to bypass the checksum by editing the version.json
Also, according to this thread offline mode will not work - the launcher will just delete the jar and refuse to launch the game; similarly, making the jar read-only also fails. Luckily, doing the above or using an older json file (if you have one, or one that was modified prior to the past couple months) without the new downloads and checksums still works.
I tried creating a new profile - didn't work, creating a new version - didn't work, and doing a different version - didn't work. I'm trying to install forge on the old release 1.2.5 but the .jar keeps resetting on startup
That's because the edited jar fails the checksum for being the wrong size, so it is considered invalid by the launcher and the launcher re-downloads it. as far as I know, the only way past that is to launch in offline mode.
[EDIT] you might also be able to bypass the checksum by editing the version.json
Creator of Metroid Cubed 3, a Metroid-themed mod! Become a donator today!
You have to remove the "downloads" argument from near the end of the json file, as shown in the following link (see the attached image):
MCL-4334 Minecraft gets reinstalled everytime you launch it
Also, according to this thread offline mode will not work - the launcher will just delete the jar and refuse to launch the game; similarly, making the jar read-only also fails. Luckily, doing the above or using an older json file (if you have one, or one that was modified prior to the past couple months) without the new downloads and checksums still works.
TheMasterCaver's First World - possibly the most caved-out world in Minecraft history - includes world download.
TheMasterCaver's World - my own version of Minecraft largely based on my views of how the game should have evolved since 1.6.4.
Why do I still play in 1.6.4?