Tracfone Samsung Galaxy S2

[Gerowen]

So my wife recently got a Samsung Galaxy S2.  It's a Tracfone version, and I wanted to root it so we could install custom firmware and such, but I'm having a problem.

When I had my Google Nexus tablet all I had to do was "adb reboot bootloader" and it would reboot me to the Android bootloader, at which point I could do "fastboot oem unlock" to unlock the phone, which would open the option for me to do whatever with it.  With this Galaxy S2 I can get "adb reboot recovery" to send me to a recovery console that lets me do a factory reset, but that's the only options on the screen, and when this is up, fastboot doesn't see the phone.  Running "adb reboot bootloader" just reboots the phone and it starts up like normal.  If I try running "fastboot devices" from the recovery console, nothing gets listed, and running "fastboot oem unlock" anyway just gives me, "Waiting for device" for as long as I'm willing to let it sit there.  Also having the same thing happen with an older Huawei phone.

The phone is bought and paid for and doesn't even have a plan or contract associated with it.  It has a pre-paid SIM in it but we just let the time run out (so now it says the SIM hasn't been provisioned) and she basically uses it like a small tablet that she can put in her pocket to use Skype and stuff on while she's in range of the wireless.

Suggestions?

[Gerowen]

So if you hold the volume down key while powering the phone off, it will send you not to a bootloader where you can issue commands via fastboot, but to a screen that warns against installing a custom OS, but allows you to download one or restart.  If you select "Yes" it goes to a screen that reads "ODIN MODE" with some system info, and I'm guessing at this point I'm supposed to be able to push a custom binary to it somehow, but even here fastboot doesn't see it as a device.

Must do more research on this.

[PGHammer]

Actually, for most Samsung devices (and this especially applies to the Tab series), you will want one of two programs - ODIN (Windows) or FOSS successor Heimdall (either Windows or most Linux distributions - primarily Ubuntu); they make use of the unique-to-Samsung "download mode" - and especially in terms of the Tabs.  For the S series (S3 and later) and Note series, you'll want the Universal Android Toolkit - unlike either ODIN or Heimdall, it will actually go and fetch stock firmware for most S-series phones or Notes; unfortunately, it can't do that for Tabs.  Still, like Heimdall, there are Windows and Linux versions available.  Because Mom has an S3, and I have her old Tab 2 (Mom replaced it with a Tab 4 when the Tab 2 had battery issues) I have the Windows versions of Odin, Heimdall, and the UAK at my beck,