Daily built Debian Installer cd kept asking for stable dists.

[Magicloud Magiclouds <magicloud.magiclouds@gmail.com>]

Hi,
  Just want to reinstall a debian box, so download the daily built iso
from cdimage.debian.org.
  Since I am out of CDR, I simply `cat the_iso.iso > /dev/udisk`. It
booted, things seemed fine until the step of finding the install cd
(sorry I cannot remember the exact menu item name now). It failed for
no valid release file for stable suite, according to the log, it
should be in /cdrom/dists/stable/. Well, this is a testing d-i, so
there is only /cdrom/dists/testing.
  Not sure if this is because the udisk boot (never tried this way
before). What should I do now?
-- 
竹密岂妨流水过
山高哪阻野云飞

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