make menuconfig
check if you have the correct target? Altera, nios2nommu, and Libc must be None.
Vendor/Product Selection --->
--- Select the Vendor you wish to target
(Altera) Vendor
--- Select the Product you wish to target
(nios2nommu) Altera Products
Kernel/Library/Defaults Selection --->
(linux-2.6.x) Kernel Version
(None) Libc Version
[*] Default all settings (lose changes)
[ ] Customize Kernel Settings
[ ] Customize Vendor/User Settings
[ ] Update Default Vendor Settings
Then <exit> <exit> <yes>
DO NOT change any other setting until first successful boot.