Comment 151 for bug 1093217

This is what worked for me.
1) Shut down laptop
2) Remove battery and unplug the power supply.
3) Press and hold power button for more than 40 seconds.
4) replace back battery and plug in power.
5) Boot into Ubuntu.Ubuntu boots normally without any delay.

Apparantly there is a bios level optimization put in by lenevo that prevents battery charging until it reches below a certain percentage. They claim this is to improve battery life. It seems that this bios level optimization messes with Ubuntu start up and hangs it.

Steps mentioned above will disable this setting and apparantly fixes ubuntu boot delay.
I have not seen boot delay after this fix for more than 3 weeks now.
I am on
~$ uname -a
Lenovo-Z580 3.8.0-33-generic #48-Ubuntu SMP Wed Oct 23 09:16:58 UTC 2013 x86_64 x86_64 x86_64 GNU/Linux

P.S. the steps mentioned above also fixes Windows 8/8.1 glitch of battery not charging even when power adapter is connected