Can't open /dev/ttyO2: No such file or directoryI realized the kernel version in the top Makefile was affecting after few git bisect runs, and then confirmed by playing with it for 3.0+ kernels.
Although I knew there was something wrong with udev and user space I didn't have the time to dig into it and just modified the version in the top Makefile while compiling the kernel (from 3.0+ to 2.6.X).
Later I discovered the issue was in my filesystem:
/etc/init.d/S10udev:19 # old kernels don't use udev case $(uname -r) in 2.6*|2.7*) ;; *) exit 0;; esacAs it turns out newer kernels don't use udev either ;) according to the script.
Removing those lines from the udev start script gives your ttyO2 console back.
This was fixed in one of the latest buildroot releases, I didn't check which one, but the udev start script doesn't have the kernel version check in buildroot 2011.08.
However, the latest version doesn't quite work for me, so, until I find some time to check what I'm missing I'll stick to 2010.08.
On a side issue:
If you ever re-download buildroot-2010.08 and build from scratch, you're likely to face a build break during:
gzip: buildroot-2010.08/dl/fakeroot_1.9.5.tar.gz: not in gzip format tar: This does not look like a tar archive tar: Exiting with failure status due to previous errorsWhich is caused by a broken fakeroot link.
http://snapshot.debian.org/archive/debian/20080427T000000Z/pool/main/f/fakeroot/fakeroot_1.9.5.tar.gzJust download from the good link and replace fakeroot tarball in:
buildroot-2010.08/dl/fakeroot_1.9.5.tar.gzAnd continue the build.