MacBook Pro 5,1 fails to boot with 2.6.32.20

Attached information was gathered under 2.6.32.19 per request by apw.

May be related to bug 561462.

Photos of the screen are at http://people.canonical.com/~bac/ubuntu/

The boot waited on the first screenshot for a couple of minutes before moving on to the initramfs BusyBox prompt.

ProblemType: Bug
DistroRelease: Ubuntu 10.04
Package: linux-image-2.6.32-20-generic 2.6.32-20.29
Regression: Yes
Reproducible: Yes
ProcVersionSignature: Ubuntu 2.6.32-19.28-generic 2.6.32.10+drm33.1
Uname: Linux 2.6.32-19-generic i686
NonfreeKernelModules: wl nvidia
AlsaVersion: Advanced Linux Sound Architecture Driver Version 1.0.21.
Architecture: i386
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: bac 2020 F.... pulseaudio
CRDA: Error: [Errno 2] No such file or directory
Card0.Amixer.info:
 Card hw:0 'NVidia'/'HDA NVidia at 0xdf480000 irq 21'
   Mixer name : 'Realtek ALC889A'
   Components : 'HDA:10ec0885,106b4000,00100103'
   Controls : 36
   Simple ctrls : 20
Date: Mon Apr 12 09:44:22 2010
EcryptfsInUse: Yes
HibernationDevice: RESUME=UUID=0783d209-c00a-4e5f-8feb-5dcdbbf1c040
InstallationMedia: Ubuntu 9.10 "Karmic Koala" - Release i386 (20091028.5)
MachineType: Apple Inc. MacBookPro5,1
ProcCmdLine: BOOT_IMAGE=/boot/vmlinuz-2.6.32-19-generic root=UUID=486270be-4fe1-4175-a24b-2987577ddb42 ro quiet splash
ProcEnviron:
 PATH=(custom, user)
 LANG=en_US.utf8
 SHELL=/bin/bash
RelatedPackageVersions: linux-firmware 1.33
RfKill:
 0: hci0: Bluetooth
  Soft blocked: no
  Hard blocked: no
SourcePackage: linux
dmi.bios.date: 05/05/09
dmi.bios.vendor: Apple Inc.
dmi.bios.version: MBP51.88Z.007E.B05.0905051508
dmi.board.asset.tag: Base Board Asset Tag#
dmi.board.name: Mac-F42D86C8
dmi.board.vendor: Apple Inc.
dmi.board.version: Proto
dmi.chassis.asset.tag: Asset Tag#
dmi.chassis.type: 8
dmi.chassis.vendor: Apple Inc.
dmi.chassis.version: Mac-F42D86C8
dmi.modalias: dmi:bvnAppleInc.:bvrMBP51.88Z.007E.B05.0905051508:bd05/05/09:svnAppleInc.:pnMacBookPro5,1:pvr1.0:rvnAppleInc.:rnMac-F42D86C8:rvrProto:cvnAppleInc.:ct8:cvrMac-F42D86C8:
dmi.product.name: MacBookPro5,1
dmi.product.version: 1.0
dmi.sys.vendor: Apple Inc.