Default [Q] S2 I9100G | Firmware upgrade encountered...

Hello,

i have the S2 I9100G and became the error "Firmware upgrade encountered an issue. Please select recovery mode in Kies & try again" . I know that i can install a stockrom and know it but my problem and my question is is there a are any chances to make a backup of my data there are really important?!

Thanks,

Reedhawk