The software exploit works for all console revisions, but the persistent softmod does not.
There exist 3 main things in the software hack space for Xbox 360:
1. BadUpdate (Grimdoomer) which is the only software hypervisor exploit for the Xbox 360. It's intended to be launched from scenarios where someone could achieve code execution. The main method for launching BadUpdate was through Rock Band Blitz (created by ihateccompvir and InvoxiPlayGames). Pure software, works across all hardware revisions of the Xbox.
2. ABadAvatar (shutterbug2000) which uses a memory corruption vulnerability in the avatar loading code in the Xbox dashboard to gain code execution after the dashboard loads, then launches BadUpdate to exploit the console. Pure software, works across all hardware revisions of the Xbox.
3. Peer Pressure (Grimdoomer). First compromises the console through one of the above methods and modifies the SMC firmware to attack the southbridge. The SMC was abused in a similar manner for the JTAG hack, which likely led to Microsoft hardening it in later revisions of the hardware and mitigating the attack used here by Grimdoomer.
More info on #3 here: https://youtu.be/ftEuor1asBM?t=96
At any rate, #1 and #2 do not provide early boot exploitation.
#3 does. The hard drive security sector is involved and the kernel is responsible for loading that, so at this stage you've gone through 2BL, hypervisor, and kernel initialization. So you can't compromise the bootloaders, but you're early enough in the boot chain to do interesting things like replacing the boot animation with something custom.
The JTAG hack does some weird stuff that, truthfully, I've never seen replicated on other hardware. tl;dr the console must be on a vulnerable software version which did not blow a downgrade fuse and using an additional hardware flash chip containing a different version of the OS which had a hypervisor bug, boots the console into that, triggers the exploit using SMC black magic, then reboots back into the upgraded version of the OS.
The RGH hack described in this article would allow you to replace 2BL, so you've compromised the console earlier in the boot chain.
There exist 3 main things in the software hack space for Xbox 360:
1. BadUpdate (Grimdoomer) which is the only software hypervisor exploit for the Xbox 360. It's intended to be launched from scenarios where someone could achieve code execution. The main method for launching BadUpdate was through Rock Band Blitz (created by ihateccompvir and InvoxiPlayGames). Pure software, works across all hardware revisions of the Xbox.
2. ABadAvatar (shutterbug2000) which uses a memory corruption vulnerability in the avatar loading code in the Xbox dashboard to gain code execution after the dashboard loads, then launches BadUpdate to exploit the console. Pure software, works across all hardware revisions of the Xbox.
3. Peer Pressure (Grimdoomer). First compromises the console through one of the above methods and modifies the SMC firmware to attack the southbridge. The SMC was abused in a similar manner for the JTAG hack, which likely led to Microsoft hardening it in later revisions of the hardware and mitigating the attack used here by Grimdoomer.
More info on #3 here: https://youtu.be/ftEuor1asBM?t=96
At any rate, #1 and #2 do not provide early boot exploitation.
#3 does. The hard drive security sector is involved and the kernel is responsible for loading that, so at this stage you've gone through 2BL, hypervisor, and kernel initialization. So you can't compromise the bootloaders, but you're early enough in the boot chain to do interesting things like replacing the boot animation with something custom.
The JTAG hack does some weird stuff that, truthfully, I've never seen replicated on other hardware. tl;dr the console must be on a vulnerable software version which did not blow a downgrade fuse and using an additional hardware flash chip containing a different version of the OS which had a hypervisor bug, boots the console into that, triggers the exploit using SMC black magic, then reboots back into the upgraded version of the OS.
The RGH hack described in this article would allow you to replace 2BL, so you've compromised the console earlier in the boot chain.