So you've got your device rooted, and you want to install a custom recovery? Great! Don't just follow any guide you stumble across though, as some of the early recovery packages for the "AT&T" model were actually just copies of the custom Sprint recovery, and then you'll have all sorts of fun trying to install ROMs. ("Status 7" errors anyone? )
I'd like to talk about 4 ways to get the custom recovery of your choice onto your device.
- Using mskip's Toolkit CWM [link]
Follow the instructions posted in his thread, and if you have any problems, direct them there as well!
- Using ROM Manager CWM [link]
For some reason, ROM Manager doesn't always offer the correct list of devices to flash a recovery for and you won't see the SGS3 (AT&T) in the list. If that happens, force-close the app from Settings > Applications and try again. If this method just won't work for you, move on to option 4.
- Using GooManager TWRP [link]
If you've been looking at ROMs, you may have noticed Goo.IM is a popular hosting website for Android developers. It's so popular, in fact, that they have produced an Android app that searches their website for updates for your ROM, and can even install TWRP with only a few simple clicks! Just open up GooManager, tap Menu, and tap "Install OpenRecoveryScript". You will be guided step-by-step from there by the app.
Note: Some people (myself included) have reported issues with this method, where the app claims to have installed the recovery, but when you reboot into recovery mode, nothing has changed. This issue may have been resolved in newer versions; I was able to successfully install TWRP using this method on Sept 26 2012.
- Manually via ADB or Terminal Emulator CWM or TWRP [Terminal Emulator link]
If the other options just won't work for you, or if you would rather do an install by hand to ensure you're getting the latest version, read on...
While this may seem difficult, it's really not. Grab a recovery image (these files end in ".img") such as ClockWork Mod (CWM) or Team Win Recovery Project (TWRP) for your device. Most ROM developers say to use CWM, but they both work equally well.
In our case, we need an image for the Samsung Galaxy S3 AT&T. Telus, Rogers, Bell, and SaskTel phones are (almost*) the exact same phone as AT&T, if you have one of these devices, you will be installing the AT&T recovery.
Now, transfer the ".img" file you downloaded onto your device. I'd suggest somewhere with a nice short path, like "/sdcard/<file>.img" (you'll thank me later, especially if you're using terminal emulator on the device)
Now, let's back up your existing recovery. If things go wrong, you can use this backup to get back to where you started.
$ su # dd if=/dev/block/mmcblk0p18 of=/sdcard/recovery-backup.img
Here's the part you've been waiting for: Flashing the new image, which installs it as your recovery system. You do this from either an ADB shell or inside Terminal Emulator.
$ su # dd if=/sdcard/<file>.img of=/dev/block/mmcblk0p18
If you need to return to the stock recovery, that IMG can be downloaded here: stock-recovery.img - 10.00 MB
*NOTE: While we're on the topic, let's take a second to talk about what makes the Canadian I747M different from the AT&T I747.
The short version is... The modem. AT&T is using completely different and incompatible modem firmware in their phones when compared with the Canadian models. Rogers, Bell, Telus, and any other Canadian I747M are the same device (Samsung worked some strange voodoo and got all the Canadian carriers to agree on the same hardware!) which means that if Rogers releases a new modem firmware update, a SaskTel user could install it without issue. AT&T modem updates will not work on Canadian models, nor will Canadian updates work on AT&T phones! I've tried it. Trust me. You don't want to deal with the hassle of fixing it.
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