Experimental approach:

### install new D6.22

lyricnz:~ simonroberts$ cd htdocs
lyricnz:htdocs simonroberts$ drush dl drupal-6.22
Project drupal (6.22) downloaded to /Users/simonroberts/htdocs/drupal-6.22.                                                                [success]
Project drupal contains:                                                                                                                   [success]
 - 1 profile: default
 - 6 themes: pushbutton, minnelli, garland, marvin, chameleon, bluemarine
 - 33 modules: user, upload, update, trigger, translation, tracker, throttle, taxonomy, system, syslog, statistics, search, profile, poll,
ping, php, path, openid, node, menu, locale, help, forum, filter, dblog, contact, comment, color, book, blogapi, blog, block, aggregator

lyricnz:htdocs simonroberts$ cd drupal-6.22
lyricnz:drupal-6.22 simonroberts$ cp sites/default/default.settings.php sites/default/settings.php
lyricnz:drupal-6.22 simonroberts$ echo "\$db_url = 'mysqli://drupal6:drupal6@localhost/drupal6';" >> sites/default/settings.php 
lyricnz:drupal-6.22 simonroberts$ drush sql-drop -y
Do you really want to drop all tables? (y/n): y
No tables to drop.                                                                                                                         [ok]
lyricnz:drupal-6.22 simonroberts$ drush site-install 
You are about to create a sites/default/files directory and DROP your 'drupal6' database and then CREATE a new one. Do you want to continue? (y/n): y
ERROR 1044 (42000) at line 1: Access denied for user 'drupal6'@'localhost' to database 'drupal6'
No tables to drop.                                                                                                                         [ok]
lyricnz:drupal-6.22 simonroberts$ 


### enable primary/secondary links blocks

Login to new site as admin, create enable primary+secondary links blocks
Set custom titles on these (so I can tell).
Add a menu item to each, linking to <front>
Take screenshot

### install new D7.7

lyricnz:drupal-6.22 simonroberts$ cd ..
lyricnz:htdocs simonroberts$ drush dl drupal-7.7
Project drupal (7.7) downloaded to /Users/simonroberts/htdocs/drupal-7.7.                                                                  [success]
Project drupal contains:                                                                                                                   [success]
 - 3 profiles: testing, standard, minimal
 - 4 themes: stark, seven, garland, bartik
 - 47 modules: drupal_system_listing_incompatible_test, drupal_system_listing_compatible_test, user, update, trigger, translation, tracker,
toolbar, taxonomy, system, syslog, statistics, simpletest, shortcut, search, rdf, profile, poll, php, path, overlay, openid, node, menu,
locale, image, help, forum, filter, file, field_ui, text, options, number, list, field_sql_storage, field, dblog, dashboard, contextual,
contact, comment, color, book, blog, block, aggregator

lyricnz:htdocs simonroberts$ cd drupal-7.7
lyricnz:drupal-7.7 simonroberts$ cp sites/default/default.settings.php sites/default/settings.php
lyricnz:drupal-7.7 simonroberts$ vi sites/default/settings.php 
lyricnz:drupal-7.7 simonroberts$ diff -u sites/default/default.settings.php sites/default/settings.php 
--- sites/default/default.settings.php	2011-07-28 10:02:24.000000000 +1000
+++ sites/default/settings.php	2011-08-10 14:50:30.000000000 +1000
@@ -177,7 +177,21 @@
  *   );
  * @endcode
  */
-$databases = array();
+$databases = array (
+  'default' => 
+  array (
+    'default' => 
+    array (
+      'database' => 'drupal6',
+      'username' => 'drupal6',
+      'password' => 'drupal6',
+      'host' => 'localhost',
+      'port' => '',
+      'driver' => 'mysql',
+      'prefix' => '',
+    ),
+  ),
+);
 
 /**
  * Access control for update.php script.
lyricnz:drupal-7.7 simonroberts$ curl -s http://drupal.org/files/issues/menu-update-primary-links-blocks-1231856_1.patch | patch -p1
patching file includes/update.inc
patching file modules/menu/menu.install
patching file modules/simpletest/tests/upgrade/drupal-6.menu.database.php
patching file modules/simpletest/tests/upgrade/upgrade.menu.test
lyricnz:drupal-7.7 simonroberts$ 


### perform upgrade via UI /update.php

Take screenshots

==> Blocks appear in the right place, no errors/warnings.