While I’m not currently using Ubuntu, I’ve been told that my script to fix Plymouth for Ubuntu 11.04 Natty works for Ubuntu 11.10 Oneirc too; lately I’m pretty satisfied by the OpenSource ATI driver, and I think that you should really give it a try as well.
Anyway, if you need it, here’s the script:

I confirm, script works for Oneiric too. Thank you so much Paolo 😉
Here on Oneiric it works partially with HD 3650. Boot loader is nice again without garbled text, but the Ubuntu logo with the red/white dots below is not the nice image, it’s just plain text.
Perhaps you know what could be the issue? Thanks!
Hi, it works for 11.10. Thanks.
However, I do have mtrr errors (kernel: [ 3.416925] mtrr: type mismatch for e0000000,1000 old: write-back new: write-combining) which does not appear to affect the performance but does affect the boot time. I tried number times to change the mtrr at e0000000 to write-combining without success. Would appreciate if you can give me some pointers as to what could be done.