[Desire Q&A, Help & Troubleshooting] Droidzone:
First, I couldnt find this on a simple search on XDA. If someone has already posted this, I apologize and will take it down. My own post is based on AVanover5's post at Androidcentral, for the LG Optimus. Full credits to him. This post is meant for sharing some info on backing up misc.

Probably many of you already know this. Some of you dont. With controversies about the recently posted Clockworkmod 3, I was trying to find a way to prevent a USB brick of my my Desire, and a way to backup my misc partition which is affected in the USB brick..

And I was wondering how to make a backup of the misc partition. Well, strictly speaking, the misc is not a file system, but a structure..

Anyway, Clockworkmod makes only the following partition backups:

cache.img

data.img

recovery.img

sd-ext.img

system.img

.android_secure.img

boot.img

So what about the others? And is there a way to backup these w/o a Clockworkmod/RA, from the adb or terminal? This definitely saves the time involved in rebooting and can allow you to create just the backup you need, and also allows you to backup the misc partition.

Initial steps: You need to find out the structure of your system with the following commands in adb (There is a terminal method, which you can read up on the original post linked above)

adb shell
su
cat /proc/mtd

You will get an output like this:

dev: size erasesize name
mtd0: 000a0000 00020000 "misc"
mtd1: 00480000 00020000 "recovery"
mtd2: 00300000 00020000 "boot"
mtd3: 0fa00000 00020000 "system"
mtd4: 02800000 00020000 "cache"
mtd5: 093a0000 00020000 "userdata"

Backing Up

Now you can backup each one to a file with the following commands:

cat /dev/mtd/mtd0 > /sdcard/misc.img
cat /dev/mtd/mtd1 > /sdcard/recovery.img
cat /dev/mtd/mtd2 > /sdcard/boot.img
cat /dev/mtd/mtd3 > /sdcard/system.img

Similiarly for the others..

Rooting is needed for this. Keep your misc.img safe.

Restoring without Nandroid

You can restore from these backups by the following commands (S-OFF needed) from the folder (on the PC) where you've copied the backups. fastboot will either have to be in the same folder, or included in the path variable.

fastboot flash boot boot.img
fastboot flash cache cache.img
fastboot flash recovery recovery.img
fastboot flash splash splash.img
fastboot flash system system.img
fastboot flash userdata userdata.img
fastboot flash misc misc.img
fastboot reboot

Note that misc flashing is supported only by the latest Alpharev. If someone knows a way to backup sd-ext similiarly, please do share the info.

Note that you can even switch these for one of the files in the Nandroid backup. You will just need to update the md5 with the correct values.

Backing up custom MTD partitions (Thanks, ieftm)

First you will have to install the Binary dump_image

[FONT=Calibri]
[SIZE=4]adb push dump_image /sdcard/[/SIZE][/FONT][SIZE=4]
[/SIZE][FONT=Calibri][SIZE=4]adb shell[/SIZE][/FONT][SIZE=4]
[/SIZE][FONT=Calibri][SIZE=4]su[/SIZE][/FONT][SIZE=4]
[/SIZE][FONT=Calibri][SIZE=4]mount -o remount,rw -t yaffs2 /dev/block/mtdblock5 /system[/SIZE][/FONT][SIZE=4]
[/SIZE][FONT=Calibri][SIZE=4]cat /sdcard/dump_image > /system/bin/dump_image[/SIZE][/FONT][SIZE=4]
[/SIZE][FONT=Calibri][SIZE=4]chmod 755 /system/bin/dump_image[/SIZE][/FONT][SIZE=4]
[/SIZE]

Once the binary is 'installed' properly, you can use it to backup your partitions.

/system/bin/dump_image misc /sdcard/misc1.img[SIZE=4]
[/SIZE]

You can use this binary for the other partitions too if you want, instead of the cat dump.

Credits:

To AVanover5 at Androidcentral, for his guide for the LG Optimus

To ieftm for sharing the flash_image method and binary

To Rastaman-FB and ieftm for correcting the errors in the OP