I got one from apple today with 1.1.2. I downgraded to 1.0.2, then installed ssh and shelled into it. Then I got the secpack40213 and tried to downgrade the baseband but it did not work. The erase basically was not able to erase it. Here is what I got:

-sh-3.2# ./ieraser
Baseband reset.
Get FlashID Request
Sending:
00000000 | 02 00 01 08 00 00 00 00 01 08 03 00 | ........ ....
0000000c
Major: 0, Minor: 0, String:
iEraser: tool by geohot
thanks to gray and the dev team for the implementation
thanks to nightwatch for the awesome toolchain
and thanks to anonymous, iProof, lazyc0der, and dinopio for the idea for this co ol trick
this tool erases your main fw, starting at 0x20000. you need this for the testpo int to work
you need a file called secpack matching your current firmware version in this fo lder
see http://iphonejtag.blogspot.com for instructions on finding this file
Waiting for data...
Got Header: 77 0b cc
02 00 85 00 02 00 FF FF 85 02 03 00
SECPACK
02 00 04 02 06 00 01 00 00 00 00 00 0B 02 03 00
02 00 02 08 06 00 00 00 00 00 00 00 08 08 03 00

Erase
02 00 05 08 02 00 00 00 07 08 03 00
02 00 06 08 06 00 01 00 00 00 A0 00 AD 08 03 00
Hopefully the main flash was erased, wait for the next step...
-sh-3.2# ./bbupdater -v
Resetting target...
pinging the baseband...
issuing +xgendata...
firmware: DEV_ICE_MODEM_04.02.13_G
eep version: EEP_VERSION:208
eep revision: EEP_REVISION:1
bootloader: BOOTLOADER_VERSION:4.6_M3S2
Done
-sh-3.2#

So either the ones apple is shipping has a DIFFERENT baseband then the one we got the secpack for or something else is messed up.

I had no problems downgrading my baseband firmware after downgrading from 1.1.2. I downgraded in 1.0.2. Did you make sure to stop the com center first?


Calvin

Looks like the difference is the bootloader. US phones are now shipping with the new bootloader which prevents erasing the baseband.

I guess party is over!

OTB 1.1.2 seems to have a different baseband bootloader, so ieraser, bbupdater and iunlock, as well as tools developed on top of them (anySIM and I'll bet IPSF) will not work unless they are fixed for the net bootloader.

This is true for the European iPhones, still waiting for confirmation from the US ones.

Same with OTB US Phone's. So comfirmed. Now i have at least to iPodTouch ;-)