The problem has been solved. schufti in
http://wl500g.info/showthread.php?t=9513&page=16 has made a new Flash-Image (MGB100_400s01) that contains ISO9660, ext3 and NTFS r/w support (experimental) using kernel 2.4.35. Works (at least for me

) but seems to be about 10% slower than the original kernel. The image is autoexec/autobootfs compatible so if you run v4, you shouldn't have a problem to use it. You will have to copy /lib/modules/2.4.35 from the RAM-disk to be able to use WLAN though.
Tes