i want to put os 6 on my blackberry curve 8520 but im not subscribed to blackberry is there any way i can install it on there without going threw blackberry ?
What error message? Are you using the exact software for your model? You just download the BB rom files from the site, you don't need a contact.
Here is a site with an over the air update, you can do it from WiFi http://www.etiole.com/2011/11/how-to-upgrade-your-blackberry-curve-8520-os-from-5-to-6/
Have not tried this though.
Also from what other sites have posted, there is no updated OS to 6 for that model, if you try to upgrade, the BB may not work afterward. http://forums.crackberry.com/blackberry-curve-85xx-f143/blackberry-curve-8520-can-upgrade-os-6-7-a-680668/