I dont believe the MTU can be changed on the Nookcolor. Have not heard this mentioned til you posted. Do your router specs list a max MTU?
There have been a large number of people here and on other boards having connectivity issues. Most of the people here have been able to make changes in their router and get it working. Some I'm sure are still fighting with it.
Would be could info to know. I guess E-mailing the manufacturer would be one way to get it.
I Found a "contact us" e-mail on the foxconn website.
I am gonna send an e-mail to WebAdmin@foxconn.com and see what I get. I'll post responce.