buildroot to build toolchain on Linux

You should find them on the nios2 doc and the forum.

You should download to ram first, and after you have a lot of tests, then download to flash.

check,

http://www.altera.com/literature/ug/ug_nio..._programmer.pdf (http://www.altera.com/literature/ug/ug_nios2_flash_programmer.pdf)

Sorry, I can not help you. I don't use CFI flash.