@Tontotrento: I can't seem to reproduce the issue on my end...
Can you double-check the files aren't corrupted? Both on your end and on the Kindle.
(Because the purpose of this specific failing check is checksum verification...).
FYI:
Code:
MD5(Update_linkss_0.24.N_install_pw2_kt2_kv_pw3_koa_kt3.bin)= c94ab5fb3c4f54c766f7882d84ea2bb3
EDIT: Err, which "updating" message, actually? Nothing should have printed anything remotely looking like that at this point...