This is what I have done: git clone git://kernel.ubuntu.com/ubuntu/ubuntu-quantal.git git clone git://www.aleph1.co.uk/yaffs2 cd ubuntu-quantal git checkout -b 3.5.0-21.32-yaffs2 Ubuntu-3.5.0-21.32 cd ../yaffs2 ./patch-ker.sh c m ../ubuntu-quantal/ cd ../ubuntu-quantal Ensured that kernel configuration is OK, i.e. yaffs2 is configured as module then `make` At the end it spits out: CC [M] fs/yaffs2/yaffs_vfs.o fs/yaffs2/yaffs_vfs.c:438:2: warning: initialization from incompatible pointer type [enabled by default] fs/yaffs2/yaffs_vfs.c:438:2: warning: (near initialization for 'yaffs_dir_inode_operations.create') [enabled by default] fs/yaffs2/yaffs_vfs.c:443:2: warning: initialization from incompatible pointer type [enabled by default] fs/yaffs2/yaffs_vfs.c:443:2: warning: (near initialization for 'yaffs_dir_inode_operations.mkdir') [enabled by default] fs/yaffs2/yaffs_vfs.c:445:2: warning: initialization from incompatible pointer type [enabled by default] fs/yaffs2/yaffs_vfs.c:445:2: warning: (near initialization for 'yaffs_dir_inode_operations.mknod') [enabled by default] fs/yaffs2/yaffs_vfs.c: In function 'yaffs_evict_inode': fs/yaffs2/yaffs_vfs.c:873:2: error: implicit declaration of function 'end_writeback' [-Werror=implicit-function-declaration] fs/yaffs2/yaffs_vfs.c: In function 'yaffs_put_super': fs/yaffs2/yaffs_vfs.c:2506:16: error: 'struct mtd_info' has no member named 'sync' fs/yaffs2/yaffs_vfs.c:2507:6: error: 'struct mtd_info' has no member named 'sync' fs/yaffs2/yaffs_vfs.c: In function 'yaffs_internal_read_super': fs/yaffs2/yaffs_vfs.c:2699:2: error: 'struct mtd_info' has no member named 'erase' fs/yaffs2/yaffs_vfs.c:2700:2: error: 'struct mtd_info' has no member named 'read' fs/yaffs2/yaffs_vfs.c:2701:2: error: 'struct mtd_info' has no member named 'write' fs/yaffs2/yaffs_vfs.c:2702:2: error: 'struct mtd_info' has no member named 'read_oob' fs/yaffs2/yaffs_vfs.c:2703:2: error: 'struct mtd_info' has no member named 'write_oob' fs/yaffs2/yaffs_vfs.c:2704:2: error: 'struct mtd_info' has no member named 'block_isbad' fs/yaffs2/yaffs_vfs.c:2705:2: error: 'struct mtd_info' has no member named 'block_markbad' fs/yaffs2/yaffs_vfs.c:2729:11: error: 'struct mtd_info' has no member named 'erase' fs/yaffs2/yaffs_vfs.c:2730:11: error: 'struct mtd_info' has no member named 'block_isbad' fs/yaffs2/yaffs_vfs.c:2731:11: error: 'struct mtd_info' has no member named 'block_markbad' fs/yaffs2/yaffs_vfs.c:2731:34: error: 'struct mtd_info' has no member named 'read' fs/yaffs2/yaffs_vfs.c:2731:48: error: 'struct mtd_info' has no member named 'write' fs/yaffs2/yaffs_vfs.c:2733:11: error: 'struct mtd_info' has no member named 'read_oob' fs/yaffs2/yaffs_vfs.c:2733:29: error: 'struct mtd_info' has no member named 'write_oob' fs/yaffs2/yaffs_vfs.c:2754:11: error: 'struct mtd_info' has no member named 'erase' fs/yaffs2/yaffs_vfs.c:2754:26: error: 'struct mtd_info' has no member named 'read' fs/yaffs2/yaffs_vfs.c:2754:40: error: 'struct mtd_info' has no member named 'write' fs/yaffs2/yaffs_vfs.c:2756:11: error: 'struct mtd_info' has no member named 'read_oob' fs/yaffs2/yaffs_vfs.c:2756:29: error: 'struct mtd_info' has no member named 'write_oob' fs/yaffs2/yaffs_vfs.c:2946:2: error: implicit declaration of function 'd_alloc_root' [-Werror=implicit-function-declaration] fs/yaffs2/yaffs_vfs.c:2946:7: warning: assignment makes pointer from integer without a cast [enabled by default] cc1: some warnings being treated as errors make[2]: *** [fs/yaffs2/yaffs_vfs.o] Error 1 make[1]: *** [fs/yaffs2] Error 2 make: *** [fs] Error 2 Jarl