I sent a mail to the list earlier, but someone helpfully pointed out
that some of the log info indicated I'd set some bad options in my
config; that has been corrected, and the issue recreated without those
options enabled.

Issue: System hangs during boot.
Affected kernel versions: 2.6.6, 2.6.7; all earlier kernel versions I
have tested work fine.
Workaround in use currently: Replace contents of
drivers/scsi/sym53c8xx_2 in 2.6.7 with contents of same dir from 2.6.5

Here's a log(copied by hand, since log never was written to HDD and no
serial to output data) of what happens when I boot an affected kernel:

sym0: <1010-33> rev 0x1 at PCI 0000:01:0a.0
sym0: Symbios NVRAM ID7, Fast 80 LVD, Parity Checking
sym0: Open drain IRQ line driver, using on chip SRAM
sym0: Handling phase mismatch from SCRIPTS
sym0: SCAN AT BOOT disabled for targets 0 1 2 3 4 5 6 7 8 9 10 11 12 13
14 15
sym0: SCAN FOR LUNS disabled for targets 0 1 2 3 4 5 6 7 8 9 10 11 12 13
14 15
sym0: SCSI bus has been reset
scsi0: sym-2.1.18j
Vendor: Quantum       Model: ATLAS10K2-TY734J      Rev: DDD6
Type: Direct-access        ANSI SCSI revision: 03
sym0:0:0: Tagged command queue enabled, command queue depth 16
scsi(0:0:0:0): Wide asynchronous
sym0:0:0: ABORT operation started
sym0:0:0: ABORT operation timed out
sym0:0:0: DEVICE RESET operation started
sym0:0:0: DEVICE RESET operation timed out
sym0:0:0: BUS RESET operation started
sym0: SCSI BUS reset detected
sym0: SCSI BUS has been reset
sym0:0:0: BUS RESET operation complete
sum0:0:0: ABORT operation started
sum0:0:0: ABORT operation timed out
sym0:0:0: HOST RESET operation started
sym0: SCSI BUS has been reset
[Hangs]

And attached are a normal dmesg from booting with the kernel I compiled,
after replacing the contents of drivers/scsi/sym53c8xx_2 with the same
from 2.6.5; also attached is the .config file I used for BOTH of these
kernels.

Hopefully somebody here can make more sense of this than I can.

Thanks in advance.