Hello Ahmed,
Thank you for your answer, in fact the installation worked fine after several attempts and I didn't strace the process soon enough to gather the most important information about dependencies. I suspect something is out of wack in 02.06 because installing for example openssh-client (or sudo as documented by another user of the forum) with opkg gives unresolved dependencies on libraries versions.
You can check this issue with: opkg update; opkg install sudo; sudo --> library not found.
And about reinstalling from the bootloader: the device is in a hard to reach location, I'll do that only on last ditch effort ...
Regards,