[Motorola Droid 4] Rick#2:
An MD5 error would indicate that your backup files don't match the checksum that was generated at the time the backups were initially generated, which most likely means that your backup files may have become corrupted... unfortunately, this can happen with any files stored on an SD card.

Don't worry too much though, there still a really good chance that you can manually restore your data, although if your MD5's aren't matching there's a tiny possibility that your backup files are toast.

*** I'll assume you are trying to restore a "safe" system backup. If it's a "non-safe" backup, then just interchange "/systemorig" and "non-safe" for "/system" and "safe", respectively. ***

You have to manually wipe your /data and /cache partitions in the wipe menu, then format "/system" in the mounts menu. This way you have a clean slate to extract your backups to.

Try this from within the console in the recovery. (Depending on whether you backed up to the internal (/emmc) or external (/sdcard) card, just mount the required partition as follows:

*** Don't worry if you get a message saying the device can't mount because it is busy, that just means it's already mounted. ***

Internal card:

{}$: mount /emmc

External card:

{}$: mount /sdcard

(To be sure, it won't hurt if you just mount both of them.)

I'll assume you used the external sdcard which is mounted at /sdcard. Now:

{}$: cd /sdcard/safestrap/backup

If you list this directory (using "ll", or "ls -l"), you'll see a list of backup directories, prefixed by either "safe" or "nonsafe" and followed by the date and time of the backup. Remember, you can use the Tab key to autocomplete file/directory names so you don't have to type in the entire path. Here's an example:

/sdcard/safestrap/backup {}$ ll
total 192
d---rwxr-x 6 1000 1015 32768 Jun 24 04:42 ./
d---rwxr-x 3 1000 1015 32768 Jun 6 04:41 ../
d---rwxr-x 5 1000 1015 32768 Jun 6 04:41 nonsafe-2012-05-25.19.22.55/
d---rwxr-x 2 1000 1015 32768 Jun 8 20:42 nonsafe-2012-06-08.13.35.00/
d---rwxr-x 2 1000 1015 32768 Jun 20 03:13 safe-2012-06-19.20.10.44/
d---rwxr-x 3 1000 1015 32768 Jun 24 13:17 safe-2012-06-23.16.25.49/
/sdcard/safestrap/backup {}$

Let's use "safe-2012-06-19.20.10.44" for my example, substitute your own directory name as I'm sure it'll be different.

Go ahead and list the contents by entering the next two commands:

/sdcard/safestrap/backup {}$: cd safe-2012-06-19.20.10.44
/sdcard/safestrap/backup/safe-2012-06-19.20.10.44 {}$: ll

You should see something like:

/sdcard/safestrap/backup {}$: cd safe-2012-06-19.20.10.44
/sdcard/safestrap/backup/safe-2012-06-19.20.10.44 {}$ ll
total 1117760
d---rwxr-x 2 1000 1015 32768 Jun 20 03:13 ./
d---rwxr-x 6 1000 1015 32768 Jun 24 04:42 ../
----rwxr-x 1 1000 1015 74135552 Jun 20 03:13 cache.ext3.tar*
----rwxr-x 1 1000 1015 225547776 Jun 20 03:12 data.ext3.tar*
----rwxr-x 1 1000 1015 201 Jun 20 03:13 nandroid.md5*
----rwxr-x 1 1000 1015 280272384 Jun 20 03:12 system.ext3.tar*
----rwxr-x 1 1000 1015 564430848 Jun 20 03:11 systemorig.ext3.tar*
/sdcard/safestrap/backup/safe-2012-06-19.20.10.44 {}$

Now that you're at the proper path for the backup you want to restore, we can manually extract the files from the backups. (If you haven't already done so, remember to wipe /data, /cache and /system.)

We have to mount /system, /data and /cache:

/sdcard/safestrap/backup/safe-2012-06-19.20.10.44 {}$ mount /system
/sdcard/safestrap/backup/safe-2012-06-19.20.10.44 {}$ mount /data
/sdcard/safestrap/backup/safe-2012-06-19.20.10.44 {}$ mount /cache

*** Don't worry if you get a message saying the device can't mount because it is busy, that just means it's already mounted. ***

/sdcard/safestrap/backup/safe-2012-06-19.20.10.44 {}$ tar xvf system.ext3.tar -C /

Wait a minute or two for it to finish, then:

/sdcard/safestrap/backup/safe-2012-06-19.20.10.44 {}$ tar xvf data.ext3.tar -C /

Wait some more... then:

/sdcard/safestrap/backup/safe-2012-06-19.20.10.44 {}$ tar xvf cache.ext3.tar -C /

Done. If you want, you can restore your /systemorig partition now but you probably don't want to do that, not if your MD5's don't match up.

Assuming you just restored a "safe" system backup and you are in "safe" mode, you can cross your fingers and reboot. If you aren't in safe mode, switch over to it from the safe-boot menu before you reboot.

At this point, you should have restored that backup manually. Hope that helps, it's always a bummer to lose your data.