Broken apt-get issue even with apt-get install -f

Question

Here's the problem. I tried to install a .deb for an epson scanner (http://download.ebz.epson.net/dsc/search/01/search/searchModule) and did accidentally installed the i386 instead of the amd64 version.

Now I get the following issue. The same issue crops up if I try to uninstall or purge using dpkg too!

sudo apt-get autoremove
[sudo] password for ***: 
Reading package lists... Done
Building dependency tree       
Reading state information... Done
You might want to run 'apt-get -f install' to correct these.
The following packages have unmet dependencies:
 iscan-plugin-gt-x770 : Depends: iscan (>= 2.16.1) but it is not installable
 iscan-plugin-gt-x820 : Depends: iscan (>= 2.22.0) but it is not installable
E: Unmet dependencies. Try using -f.
➜  ~  sudo apt-get install -f
Reading package lists... Done
Building dependency tree       
Reading state information... Done
Correcting dependencies... Done
The following packages were automatically installed and are no longer required:
... libreoffice-java-common...linux-image-extra-3.11.0-13-generic linux-image-extra-3.11.0-14-generic
  linux-image-extra-3.11.0-15-generic lp-solve openjdk-7-jre-lib swig swig2.0
Use 'apt-get autoremove' to remove them.
The following packages will be REMOVED:
  iscan-plugin-gt-x770 iscan-plugin-gt-x820
0 upgraded, 0 newly installed, 2 to remove and 3 not upgraded.
After this operation, 926 kB disk space will be freed.
Do you want to continue [Y/n]? y
(Reading database ... 693386 files and directories currently installed.)
Removing iscan-plugin-gt-x770 ...
/var/lib/dpkg/info/iscan-plugin-gt-x770.prerm: 4: /var/lib/dpkg/info/iscan-plugin-gt-x770.prerm: iscan-registry: not found
dpkg: error processing iscan-plugin-gt-x770 (--remove):
 subprocess installed pre-removal script returned error exit status 127
No apport report written because MaxReports is reached already
                                                              /var/lib/dpkg/info/iscan-plugin-gt-x770.postinst: 4: /var/lib/dpkg/info/iscan-plugin-gt-x770.postinst: iscan-    registry: not found
Removing iscan-plugin-gt-x820 ...
/var/lib/dpkg/info/iscan-plugin-gt-x820.prerm: 4: /var/lib/dpkg/info/iscan-plugin-    gt-x820.prerm: iscan-registry: not found
dpkg: error processing iscan-plugin-gt-x820 (--remove):
subprocess installed pre-removal script returned error exit status 127
No apport report written because MaxReports is reached already
                                                              /var/lib/dpkg/info/iscan-plugin-gt-x820.postinst: 4: /var/lib/dpkg/info/iscan-plugin-gt-x820.postinst: iscan-    registry: not found

Errors were encountered while processing:
 iscan-plugin-gt-x770
 iscan-plugin-gt-x820
E: Sub-process /usr/bin/dpkg returned an error code (1)

Answer 1

Try:

echo | sudo tee /var/lib/dpkg/info/iscan-plugin-gt-x770.prerm
echo | sudo tee /var/lib/dpkg/info/iscan-plugin-gt-x820.prerm

And then:

sudo apt-get install -f

The above commands will empty the pre removing scripts on the packages and therefore will make the uninstaller finish correctly.