This patch adds the possibility to compress a initrd with lzma, you need ths CONFIG_BLK_DEV_RAM_LZMA build option for this. (Device Drivers -> Block devices) For example the debian installer initrd: -rw-r--r-- 1 ijuz ijuz 2870355 Mar 5 20:00 initrd.gz -rw-r--r-- 1 ijuz ijuz 2158769 May 8 02:09 initrd.lzma You can in theory also compress the kernel image itself with it, use the correspondign option... BUT it doesn't work for some reason (the lzma tool has to be in arch/i386/boot/compressed for this) http://debian.christian-leber.de/kernel_lzma/LZMA_C.tar.gz with this tool you can decompress lzma files and it also shows you a crc32 checksum, so you can see that the kernel image decompression actually works, but the kernel doesn't boot. Perhaps somebody can give me a hint, i'm completly lost. (arch/i386/boot/compressed/misc_lzma.c the decompress_kernel the gzip version is the misc.c) Size example for the kernel image: -rw-r--r-- 1 ijuz ijuz 1215744 May 15 03:16 vmlinux.bin.gz -rw-r--r-- 1 ijuz ijuz 1086578 May 15 17:24 vmlinux.bin.lzma Building the lzma tool cut and paste style: mkdir build-lzma wget http://www.7-zip.org/dl/lzma417.tar.bz2 tar xjf lzma417.tar.bz2 cd SRC/7zip/Compress/LZMA_Alone/ make cp lzma ../../../../../ cd ../../../../../ Christian Leber 2005