Hi Abi, thanks for following up.
Yeah I actually did it with the "delete all" command the first time (I did it again then, but but it doesn't change anything).
I've just tried the tool you suggest me; I had to run it on a virtual machine with Win 7 as on my computer I have Windows Vista and it was not compatible. But after I connected the phone under Nokia Software Recovery Tool, it only proposed me to upgrade to
"software version 10.24", which seemed to be related to firmware as it was also said I had to leave the phone connected and not removing it during the update or it could make it stop working... But that's strange I can't find any track of a firmware v.10.24
for Nokia Asha 208 on Nokia dev website for instance (only on some alternative firmware download websites).
The upgrade actually didn't work out (stopped at 10%), but that may be because the virtual machine (i'll try to test on another computer if you think it can help). No harm to my phone though, and I tried to check for FOTA upgrade via the phone, but it says
no firmware update available...
SMS and Gallery still sync with Nokia Suite... And still this Contacts error message only...