All useful threads will be added to this global sticky, if you feel a thread is worth of inclusion then please pm a mod with the details and we'll look it over. Before doing anything else You need to back up your IMEI. On very rare occasions your IMEI can get corrupted while flashing a new rom, and if you don't have a copy of the file you are essentially done for. So make sure you do this first. [HOW TO] /efs Folder backup + Restore NV_DATA.BIN You only need to to do this once. So take your time and get it done first. Rooting and Unrooting Layman's guide to rooting your I9000. If you are on 2.1, download this file. File name: 2_1_root_update.zip File size: 1.20 MB Put it on the root of your internal SD (that means not inside any folders), enter recovery mode and choose "install update.zip". If you are on 2.2, download z4root. It is no longer available on the market. For some reason RyanZA has decided to pull it. But you can still download it [here]. If you are on 2.2.1, get Super One Click. [LINK] If you are on 2.3 or above, well.... if you are already flashing beta roms, you should already know how to do this. How to UNROOT your phone. The quickest and cleanest way is to simply flash a stock firmware. You might have to delete the super user app afterwards. To check whether you still have root afterwards, check out this guide. XDA - Unroot any android device Alternatively, try Super One Click. Obviously, if you couldn't root your phone with Super One Click, most likely you won't be able to unroot it using this method either. Lagfixes Why is my phone lagging To make a long story short, your phone lags because Samsung chose an old file system that is more robust, but less efficient. Lagfixes involves changing the file system from RFS to ext4 (or ext2 on older lagfixes). Which file system should I use? Ext4 or Ext2 Ext4 is more reliable and less prone to corruption than Ext2, hence always choose Ext4 if possible. So how do I install a lagfix? If you are still on 2.2 or 2.1, it's "safe" to go with RyanZA's OCLF. It's easy to use, and it saves you from having to root your phone using a different process. However, it uses Ext 2 instead of Ext 4. Also, you cannot remove the lagfix while in recovery mode, meaning that if your phone died, you will have to flash another rom while the lagfix is still ACTIVE. If you are on 2.2.1 or higher, you MUST install a lagfix capable kernel instead of OCLF. OCLF does not support 2.2.1 or any newer roms, and has been know to cause problems. Instead, install a kernel that supports lagfix (which includes practically every single kernel out there). There are two major fractions of lagfix kernels. Universal Lagfix and Voodoo lagfix. Personally I cannot tell the different between the two of them. Here are a list of some of the more popular kernels. Froyo Kernels [Kernel]Speedmod Froyo [Kernel]Tegrak Lagfix [Kernel]Advanced Voodoo [KERNEL][VoodooSnd4-VSF-OC-TRCU-BFQ-ZRAM] Super Optimized Kernel [KERNEL] DamianGTO Ultimate kernel Gingerbread Kernel [KERNEL] DamianGTO Ultimate Ginger Kernel [KERNEL] Hacked Lagfix/Ext4 Samsung Galaxy S Gingerbread - JVK *DO NOT ATTEMPT TO INSTALL A GINGERBREAD KERNEL ON FROYO OR VICE VERSA* Instructions for installing kernels Spoiler Open Odin. Put the kernel file (should a single file with extension .tar) in PDA. Leave CSC, Phone and PIT blank. Make sure repartition is NOT checked. Put your I9000 in download mode, and then plug it in. Flash. Done. Official Roms Official Samsung Roms/Firmware Custom Roms There are dozens of custom roms, and each of them has their own peculiar way of installation. So make sure you read the instructions carefully before flashing. Most of the time in involves entering CWM recovery and installing it as a zip file. If you are still on eclair, you can probably rename the rom as update.zip and install it the same way as you would root your phone, but I wouldn't recommend it. Instead download this. File name: CWM_update.zip File size: 1.72 MB Enter Recovery mode and choose "install update.zip". You might need to do this twice to get into clockwork recovery. Once you do, you can now select "install from zip" and browse for the rom file. The rom file has to be on the internal SD instead of the external, else you won't be able to find it. P.S. Use the volume button to navigate, power button to select while in CWM recovery, as opposed to the home button in stock recovery.