Here is a FTF of 10.3.A.0.423 Generic NCB (Unbranded/Nordics Combined) downloaded through Sony PC Companion. Enjoy!
Device: C6603
Build number: 10.3.A.0.423
Android version: 4.2.2
Customization version: 1270-7280
Country: Nordic Combined
Branding: Generic NCB
C6603_10.3.A.0.423 _Generic NCB.part1.rar [Dev-Host]
C6603_10.3.A.0.423 _Generic NCB.part2.rar [Dev-Host]
Device: C6603
Build number: 10.3.A.0.423
Android version: 4.2.2
Customization version: 1270-7280
Country: Nordic Combined
Branding: Generic NCB
C6603_10.3.A.0.423 _Generic NCB.part1.rar [Dev-Host]
C6603_10.3.A.0.423 _Generic NCB.part2.rar [Dev-Host]