I picked up a LS Live 250 a few days ago. I just finished installing the LS Pro Genlink image onto it, and it works very well.
The installation process principles are the same as for the LS Pro, but there seem to be some differences in the way that booting is handled. Here is a quick overview of what I did, I can post further details on request.
1) Fetch original firmware + W32 flasher tool from Buffalo FTP server
2) Unpack, modify and repack rootfs (hddrootfs.buffalo.updated) to spawn telnetd. Simply edit /etc/init.d/rcS to include the line
/usr/sbin/telnetd -l /bin/bash
This gives telnet root access to the stock firmware. Flash this firmware copy using the windows flash tool (It is in japanese but you can figure it out by clicking around ... the password entry field wants to have the 'admin' password).
3) To enter "EM" mode (use initrd as root fs), de-ubootize, ungzip and loop-mount initrd.buffalo, then modify /linuxrc to always use ramdisk booting mode (look at the bottom of the file ...). Also enable telnetd in /etc/init.d/rcS like in step 2. Unmount, gzip and re-add the u-boot header with mkimage from the u-boot tools. Then scp the resulting initrd.buffalo to the LS and replace the existing one in /boot. Sync, reboot and telnet into the LS again.
4) Partition the HD (leaving only sda1 intact) and install Genlink up to the reboot step. To enable booting Genlink, generate another initrd.buffalo (like in step 3) where /linuxrc only consists of:
echo "---- in linuxrc ---"
mount proc /proc -t proc
# set the system time from the hardware clock
## Setup Micon communication port and send flash-boot complete message.
miconapl -b -a boot_flash_ok
### miconapl -a led_set_cpu_mcon off
### miconapl -a led_set_on_off off
### miconapl -a led_set_brink off
### miconapl -a fan_set_speed full
Install that initrd.buffalo in /boot, sync and reboot. Voila, genlink should come up after 1-2 minutes.