Comment 8 for bug 553854

Another (shorter) workaround suggests to set the native screen resolution as GRUB_GFXPAYLOAD_LINUX in /etc/default/grub:
http://ubuntuforums.org/showthread.php?t=1469475

It wasn't sufficient for me however, and I had to follow the whole process at http://news.softpedia.com/news/How-to-Fix-the-Big-and-Ugly-Plymouth-Logo-in-Ubuntu-10-04-140810.shtml to eventually fix the problem (with nVidia ION hardware / nvidia-glx)

Even if only cosmetic, I find this bug rather problematic: indeed, the crippled logo is the first thing a user will see when powering up his system, and the last when powering down, setting the mood for the whole experience...