docs/shell: Give users some hints on what to do if encoding/decoding fails

Change-Id: I557991da748126f3585b88b27706b29e0264635b
Related: OS#6385
diff --git a/docs/shell.rst b/docs/shell.rst
index 487d22e..a27c450 100644
--- a/docs/shell.rst
+++ b/docs/shell.rst
@@ -505,6 +505,9 @@
    :module: pySim.filesystem
    :func: LinFixedEF.ShellCommands.read_rec_dec_parser
 
+If this command fails, it means that the record is not decodable, and you should use the :ref:`read_record`
+command and proceed with manual decoding of the contents.
+
 
 read_records
 ~~~~~~~~~~~~
@@ -519,6 +522,9 @@
    :module: pySim.filesystem
    :func: LinFixedEF.ShellCommands.read_recs_dec_parser
 
+If this command fails, it means that the record[s] are not decodable, and you should use the :ref:`read_records`
+command and proceed with manual decoding of the contents.
+
 
 update_record
 ~~~~~~~~~~~~~
@@ -533,6 +539,9 @@
    :module: pySim.filesystem
    :func: LinFixedEF.ShellCommands.upd_rec_dec_parser
 
+If this command fails, it means that the record is not encodable; please check your input and/or use the raw
+:ref:`update_record` command.
+
 
 edit_record_decoded
 ~~~~~~~~~~~~~~~~~~~
@@ -551,6 +560,12 @@
 
 This allows for easy interactive modification of records.
 
+If this command fails before the editor is spawned, it means that the current record contents is not decodable,
+and you should use the :ref:`update_record_decoded` or :ref:`update_record` command.
+
+If this command fails after making your modificatiosn in the editor, it means that the new file contents is not
+encodable; please check your input and/or us the raw :ref:`update_record` comamdn.
+
 
 decode_hex
 ~~~~~~~~~~
@@ -579,6 +594,8 @@
    :module: pySim.filesystem
    :func: TransparentEF.ShellCommands.read_bin_dec_parser
 
+If this command fails, it means that the file is not decodable, and you should use the :ref:`read_binary`
+command and proceed with manual decoding of the contents.
 
 update_binary
 ~~~~~~~~~~~~~
@@ -632,6 +649,10 @@
       "extensions": "ff"
   }
 
+If this command fails, it means that the file is not encodable; please check your input and/or use the raw
+:ref:`update_binary` command.
+
+
 edit_binary_decoded
 ~~~~~~~~~~~~~~~~~~~
 This command will read the selected binary EF, decode it to its JSON representation, save
@@ -645,6 +666,12 @@
 
 This allows for easy interactive modification of file contents.
 
+If this command fails before the editor is spawned, it means that the current file contents is not decodable,
+and you should use the :ref:`update_binary_decoded` or :ref:`update_binary` command.
+
+If this command fails after making your modificatiosn in the editor, it means that the new file contents is not
+encodable; please check your input and/or us the raw :ref:`update_binary` comamdn.
+
 
 decode_hex
 ~~~~~~~~~~