Xan,
I'm not an expert on these issues, but I'll try to answer as best as I can.
Mmm.... what this mean? What is the "archive"?
Is there any site from downloading the fixed version?
You don't need to download anything new. Just use the beta installer you
can download from Martin Michlmayer's page, and it will download the
"archive" in the course of the installation process.
For the other hand, can you light me in migration from unslung to
debian. How can I pass from one to another? Could I follow a similar
process of migration from original Linksys firmware to debian (update
firmware), or I must update that with upslug2? I can't find any
"migration" page in nslu2-linux or in your page.
AFAIK, with unslung you still have the original Linksys web interface.
Just use the "update firmware" function of that web interface to flash the
debian installer. See Martin's website for instructions.
HTH, Richard