[Nexus One Android Development] Rattamahatta:
Did a fresh install (i.e. wiped everything, formatted ext-partition) and followed your guide to copy the mount scripts.

The system doesn't boot. Right after startup logcat prints the following error:

I/mountext( 90): Checking /dev/block/mmcblk0p2 for errors...
I/run-parts( 74): e2fsck 1.41.11 (14-Mar-2010)
I/run-parts( 74): /dev/block/mmcblk0p2: recovering journal
I/run-parts( 74): Pass 1: Checking inodes, blocks, and sizes
I/run-parts( 74): Pass 2: Checking directory structure
I/run-parts( 74): Pass 3: Checking directory connectivity
I/run-parts( 74): Pass 4: Checking reference counts
I/run-parts( 74): Pass 5: Checking group summary information
I/run-parts( 74): /dev/block/mmcblk0p2: ***** FILE SYSTEM WAS MODIFIED *****
I/run-parts( 74): /dev/block/mmcblk0p2: 25/62592 files (0.0% non-contiguous), 8391/250050 blocks
I/run-parts( 74): mount: can't read '/etc/fstab': No such file or directory
I/mountext( 101): /data successfully mounted
I/run-parts( 74): /system/etc/init.d/10a2sd2[42]: [: missing ]
I/run-parts( 74): grep: ]: No such file or directory
I/run-parts( 74): mv: can't rename '/sd-ext/app/*': No such file or directory
I/run-parts( 74): mv: can't rename '/sd-ext/app-private/*': No such file or directory
I/run-parts( 74): mv: can't rename '/sd-ext/data/*': No such file or directory
I/run-parts( 74): /system/etc/init.d/10a2sd2[105]: [: !=app: unexpected operator/operand
I/run-parts( 74): /system/etc/init.d/10a2sd2[105]: [: !=app: unexpected operator/operand
I/run-parts( 74): /system/etc/init.d/10a2sd2[105]: [: !=app: unexpected operator/operand
I/run-parts( 74): /system/etc/init.d/10a2sd2[105]: [: !=app: unexpected operator/operand
I/run-parts( 74): /system/etc/init.d/10a2sd2[105]: [: !=app: unexpected operator/operand
I/run-parts( 74): /system/etc/init.d/10a2sd2[105]: [: !=app: unexpected operator/operand
I/run-parts( 74): /system/etc/init.d/10a2sd2[105]: [: !=app: unexpected operator/operand
I/run-parts( 74): /system/etc/init.d/10a2sd2[126]: [: !=app: unexpected operator/operand
I/run-parts( 74): /system/etc/init.d/10a2sd2[126]: [: !=app: unexpected operator/operand
I/run-parts( 74): /system/etc/init.d/10a2sd2[126]: [: !=app: unexpected operator/operand
I/run-parts( 74): /system/etc/init.d/10a2sd2[126]: [: !=app: unexpected operator/operand
I/run-parts( 74): /system/etc/init.d/10a2sd2[126]: [: !=app: unexpected operator/operand
I/run-parts( 74): /system/etc/init.d/10a2sd2[126]: [: !=app: unexpected operator/operand
I/run-parts( 74): /system/etc/init.d/10a2sd2[126]: [: !=app: unexpected operator/operand
I/run-parts( 74): /system/etc/init.d/10a2sd2[126]: [: !=app: unexpected operator/operand
I/run-parts( 74): /system/etc/init.d/10a2sd2[126]: [: !=app: unexpected operator/operand
I/run-parts( 74): com.android.*: No such file or directory
I/run-parts( 74): com.google.android.*: No such file or directory
I/run-parts( 74): com.cyanogenmod.*: No such file or directory
I/run-parts( 74): com.keramidas.TitaniumBackup: No such file or directory
I/run-parts( 74): *: No such file or directory

Edit: This might be interesting too:

E/dalvikvm( 123): Could not stat dex cache directory '/data/dalvik-cache': No such file or directory
I/dalvikvm( 123): Unable to open or create cache for /system/framework/core.jar (/data/dalvik-cache/system@framework@core.jar@classes.dex)
D/dalvikvm( 123): Unable to process classpath element '/system/framework/core.jar'
E/dalvikvm( 123): Could not stat dex cache directory '/data/dalvik-cache': No such file or directory
I/dalvikvm( 123): Unable to open or create cache for /system/framework/core-junit.jar (/data/dalvik-cache/system@framework@core-junit.jar@classes.dex)
D/dalvikvm( 123): Unable to process classpath element '/system/framework/core-junit.jar'
E/dalvikvm( 123): Could not stat dex cache directory '/data/dalvik-cache': No such file or directory
I/dalvikvm( 123): Unable to open or create cache for /system/framework/bouncycastle.jar (/data/dalvik-cache/system@framework@bouncycastle.jar@classes.dex)
D/dalvikvm( 123): Unable to process classpath element '/system/framework/bouncycastle.jar'
E/dalvikvm( 123): Could not stat dex cache directory '/data/dalvik-cache': No such file or directory
I/dalvikvm( 123): Unable to open or create cache for /system/framework/ext.jar (/data/dalvik-cache/system@framework@ext.jar@classes.dex)
D/dalvikvm( 123): Unable to process classpath element '/system/framework/ext.jar'
E/dalvikvm( 123): Could not stat dex cache directory '/data/dalvik-cache': No such file or directory
I/dalvikvm( 123): Unable to open or create cache for /system/framework/framework.jar (/data/dalvik-cache/system@framework@framework.jar@classes.dex)
D/dalvikvm( 123): Unable to process classpath element '/system/framework/framework.jar'

Edit2: Well, I looked through the script and found the problem. The directory 'dalvik-cache' just didn't exist on the sd-ext partition. I had to create it manually and the system boots as it should.

Should be an easy fix to add a check if the directory exist, and if not, to create it.

Edit3: Found another problem. /data/misc doesn't exist although it exists in /sd-ext/misc. Symlinking the directory solves the problem (temporarily).