Finally I got it compiled.
You can use now the usb2serial converters which uses the cp210x chipset.
more information here:
http://www.chip45.com/index.pl?page=littleUSB_Downloads&lang=de
the cp210x.tar.gz includes the obects and scripts to load/unload the driver
the cp210x_src.tar.gz includes the src which can be compiled by copying the tarball to the usr_src/ directory of the firmeware source tree.

Have fun !

Are you just using the USBFS from the downloads section of macsat.com - or which distro are you using?

*** This version works alone BUT i don't know if it works with previous USB filesystems. ***
*** Only for test alternate distributions like openwrt ***

Some modules for the kernel and a "test" v4 firmware image. Modules work with all kernel versions.
for modules: cd /lib;tar -xzf modules.tar.gz
It should work with any i386/486sx linux version in USB or HD (WITH telnetd and network configured).
Kernel has it's own recovery system MGB100_GPL/linux_src/arch/i386/boot/setup.S and we can't change it but...
Make a grep -ir lily MGB100_GPL/linux_src/* to see changes in kernel. A lot of them...

/sbin/init included. (post changes to do it better)

#!/bin/sh
# Search autoinit file in devices -script to execute before init-
# and search autobootfs -file with ext2 fs- to mount and boot inside.
#
PATH=/bin:/sbin
mount -t proc none /proc
for altboot in sda1 sda2 sdb1 sdb2 hda1 hda2 hda3; do {
        mount /dev/$altboot /mnt
        if [ -f /mnt/autoinit ];then
                echo Found AutoInit in device: $altboot
                umount /proc
                cd /mnt
                mkdir ramroot
                pivot_root . ramroot
                exec /autoinit
        fi ;
        if [ -f /mnt/autobootfs ];then
                echo Found AutoBootFs in device: $altboot
                insmod loop
                mkdir /bootfs
                losetup /dev/loop0 /mnt/autobootfs
                mount /dev/loop0 /bootfs
                umount /proc
                cd /bootfs
                mkdir ramroot
                pivot_root . ramroot
                exec /autoinit
                exec /sbin/init
        fi ;
        umount /mnt
        echo Testing $altboot for autoinit file: NO
}; done
#
# No alternate boot found. Restore init and boot ram
#
umount /proc
mv /sbin/init /sbin/init.altboot
ln -s ../bin/busybox /sbin/init
exec /sbin/init
=========================

The /sbin/init file search for autoinit in storage devices and run it as pid 1. autoinit can umount ram0 and exec /sbin/init
It also search for a autobootfs (ext2 image) and mount it as root device, its usefull for vfat devices or single file.
The /etc/rc.d/rc.bridge file calls autoexec script to fix changes in firmware. It can load modules or execute daemons...
I dont know if it works with v3 usb filesystem.

Openwrt x86 Kamikaze image is working but it lacks samba server and webif^2 must be adapted to configure it.

The autoinit is:

exec /sbin/init

My configure system file /etc/init.d/rcS

#!/bin/sh
PATH=/bin:/sbin:/usr/bin:/usr/sbin
mount -t proc none /proc
insmod rt2500
rt2500apd
#Wireless Network settings must be in /tmp/RT2500AP.dat and info about it in MGB100_GPL/linux_src/drivers/net/wireless/rt2500/README
ifconfig wl0  0.0.0.0 up ;
ifconfig eth1 0.0.0.0 hw ether 00:80:5A:49:70:69 up &
ifconfig lo   127.0.0.1 up
/etc/init.d/dropbear start &

# Remove comments to release memory.
#umount /ramroot
#freeramdisk /dev/ram0
#rmdir /ramroot

brctl addbr br0
brctl addif br0 eth1
brctl addif br0 wl0
ifconfig eth1 0.0.0.0
ifconfig wl0  0.0.0.0
ifconfig br0 192.168.2.10 up
route add default gw 192.168.2.1 &
echo nameserver 192.168.2.1 > /etc/resolv.conf
====================

My RT2500AP.dat

[Default]
SSIDNum=1
SSID=WHD.AP.NAME *******change it*****
HideSSID=0
CountryRegion=6
WirelessMode=0
TxRate=0
Channel=7
BeaconPeriod=100
DtimPeriod=3
TxPower=50
BGProtection=0
TxPreamble=0
RTSThreshold=2347
FragThreshold=2346
TxBurst=0
TurboRate=0
NoForwarding=0
ShortSlot=0
AutoChannelSelect=0
AuthMode=WPAPSK
EncrypType=TKIP
WPAPSK=wpa.password ******change it *****
IEEE8021X=0
ReKeyMethod=DISABLE
ReKeyInterval=
AccessPolicy=0
AccessControlList=
WdsEnable=0
WdsNum=0
WdsList=
====================

I am aware of the 0 kbyte downloads.

You can now find both files in the downloads section of the site:

http://www.macsat.com/macsat/component/option,com_docman/task,cat_view/gid,22/Itemid,63/

Hi ender_x, I'll try answering a couple of your questions. The USB and filesystem drivers are compiled into the kernel, and only the closed-source wireless driver comes as a module. I think the .bin is a flash image which contains both the kernel and a compressed root file system that the kernel unpacks into ram at start-up. I don't know how the kernel is actually booted, but I assume it's something like RedBoot.

I agree about the "update" name, but "MGB100" wouldn't be great either, because there a number of different brands, and this particular update is actually based on the Conceptronic version. Also, "linuxrc" wouldn't be suitable because that's intended for initrds and is expected to do any necessary setup and exit before the kernel invokes init, whereas "autoinit" is itself intended to hand over to the actual init.

http://gepage.googlepages.com/autobootfs..whd.v4.gz

gunzip (30mb)
rename to autobootfs
drop in your boot device

If you have an autoinit in the same device, autobootfs will be ignored.
Its original firmware, with some utilities in /usr/bin

Make your own changes/tools and share it 

If I understand it correctly, it's the replacement for the "HDD/USB Filesystem for V3" to go with Pagano's firmware V4. But unlike that it's not a tgz that you need to untar into the root of an ext2 partition, instead it's a (gzipped) filesytem image that can directly be mounted. Firmware V4 tries to mount an image called 'autobootfs' if it can't find an 'autoinit' to execute. I think the advantage is that you can simply stick it on a FAT disk, i.e. you don't need to format with ext2.

ps: I've now got Debian booting properly using autoinit, so that runlevels and shutdown work correctly, and the only part of the firmware left running is the kernel. Also added "umount -l /ramroot" to autoinit to free up the ramdisk. Great work, Pagano, thank you very much again.