Sorry - trade secret. J/K...
1) Removed encrypting filter settings (meaning 723fb954-d931-4348-b672-82a188e587b5.rgu and boot_ms.rgu are no longer required and have been removed)
2) Removed IRDA protocol stack since there is no IR device in the CDMA Touch Pro
3) Set the File System Replication Filter (fsreplxfilt) as follows:
...Set the DoImmaculate flag - causes the OID mapping cache to be flushed at boot - prevents leftover stale entries.
...Set the OID cache size to 4096 entries
4) Removed all references to the relfsd (Release File System) - this file system is for development and is not (as far as I know) used by the OS
5) Instantiated CacheFilt.dll in the filters section on the SDMemory and FLASHDRV profiles. The way it was instantiated in boot.rgu it was being over-ridden by profile-level filter entries. IMHO, the default boot.rgu is NOT using the file cache filter. I also added the LockIOBuffers key - per MS, this key is required if using the file cache filter with the file system replication filter.
6) Removed MSFlash and CD profiles from file system since these do not exist in CDMA Touch Pro
7) Removed spy file system. This appears to be a leftover simple sample file system that MS provides developers.
FLASHDRV profile FATFS
... Disabled Autoscan in flags key (flags key shoud be deprecated but I kept it for backwards compatibility)
... Disabled Autoscan via new WM6 key
... Changed DataCacheSize from 2048 sectors to system-managed. This is the directory meta-data. Since most of the files on your system are in IMGFS, this will basically result in Windows deciding how much directory meta-data to cache, which will usually be all of it unless you have a ton of stuff installed (vs. cooked in).
... Changed FatCacheSize from 512 sectors to system-managed. Same comments as above apply.
... Set transaction bitmap cache size to system-managed (which should be the default if this key isn't specified) - so this may not represent a change.
... Enabled pre-loading of the FAT and transaction bitmap caches at boot time (slows boot but speeds up initial performance, no long-lasting performance impact). Not sure if this change is worth keeping.
9) Removed HTC Filter (no idea what it does and all builds I've done have worked fine without it)
10) Moved lsfilter from XIP to IMGFS (lsfilter is part of the LockStream Digital Rights Management solution HTC is using).
Note - I discovered that the Flags key under HKLM\Init\Bootvars is different. Not sure why - I didn't intentionally change this. I don't know what this value does. I can upload a new version with this changed back and you can try it.
What Pagepool size are you using?