This workaround [1] let me upgrade to Precise final.
[1] http://aaron-kelley.net/blog/2012/04/upgrade-from-ubuntu-11-10-oneiric-to-ubuntu-12-04-lts-precise-fails-with-error-couldnt-configure-pre-depend-libtinfo5-for-libncurses5-probably-a-dependency-cycle/
This workaround [1] let me upgrade to Precise final.
[1] http:// aaron-kelley. net/blog/ 2012/04/ upgrade- from-ubuntu- 11-10-oneiric- to-ubuntu- 12-04-lts- precise- fails-with- error-couldnt- configure- pre-depend- libtinfo5- for-libncurses5 -probably- a-dependency- cycle/