Apple has posted the Verizon iPhone 4 firmware to its servers for public download.
You can download the iOS 4.2.6 firmware from here. MuscleNerd has posted the keys for anyone who’s interested.
Apparently, there is some hope that limera1n might work to jailbreak the firmware since the i4 crypto engine was able to get the keys.
If the i4 crypto engine couldn’t get those, it would have been bad sign for limera1n. But it did, so there’s still hope.