Just got done soldering, dumping, updating, dumping, starting games, and dumping again. This was on my Xenon console that was unbanned by MS. There's some serious changes going on with the bootloader and CB. Here are before and after dumps in 360 Flash Dump Tool.
2BL [CB] has changed from 7373 to 7377. This value has the final say whether your console can be Jtag'd/RGH'd. The 2BL number depends on the motherboard revision.
4BL [CD] shows up empty.
5BL [CE] has changed from 1888 to 5968. 5BL has been the same on every console and dash version since Adam walked out of the Garden of Eden. It's never changed. 360FDT also shows the Nand as "Retail Unknown Model" instead of "Retail Xenon (v1.0)".
The latest version of 360FDT is from 2010. So I started thinking, "Maybe MS changed the format of the Nand a little so that 360FDT can't fully read it anymore."
For those few of us who have played around with the newest RGLoader (turns your RGH console into a DevKit), a newer tool came with it called RGBuild2. I opened the 14717 dump in it and I was right.
RGBuild2 shows a 2-stage CB along with the following values:
CB_A (2BL) = 7377
CB_B (2BL) = 7377
CD (4BL) = 7377
CE (5BL) = 1888 (Still the same)
6BL and 7BL are still the same. 360FDT now reads a wrong value for 4BL and 5BL.
For illustration, here's a Nand dump from my MS-refurbished Jasper with a 2-stage CB. It has an 3BL [CB] value (2BL[CBv1] = CB_A; 3BL[CBv2] = CB_B).
360FDT should have showed something similar from my Xenon 14717 Nand dump, so MS obviously changed some things around in the bootloader. 2-Stage CB's prevent PHAT consoles from being RGH'd. This could very well be the start of MS cutting down on the number of RGH-able consoles.
I know the above is little over most of your heads and you just want to know if anything has changed as far as backups go. This console was flag-free before I updated. After updating, I started a couple of XGD3 games offline and online and dumped the Nand again. Still no flags.
I don't have the CPU key of this console, so even if did know what to look for as far as new security scheme changes, I couldn't decrypt the KV anyway. As of 3:30 PM MST, none of my other online consoles (3 of them) still haven't asked for the update.
My instinct says there's nothing in this to try to counter LT+ 3.0 but I'm no authority on anything so take it with a grain of salt.