[Galaxy Grand Duos i9082 Q&A, Help & Troubleshootin] kinggimped:
mr_coimbatore, I'm having exactly the same problem with a China Unicom I9082 here in Shanghai. Sadly I still haven't been able to find a solution, after weeks of searching.

It's actually a friend's phone, he bought it because he wanted a dual SIM Android handset, though foolishly bought it straight from Unicom rather than from an electronics market. I told him I'd get rid of the China Unicom firmware for him as it is obviously crippled by design like all Chinese Android stock ROMs. I've managed to install k2wl's Ultralite ROM on the handset but I'm facing the same issue as you - the baseband remains untouched from the one that was on the original ROM (I9082ZNAMB3), but it's stuck in flight mode. Can receive calls/texts, cannot make them.

The big clue that there is some kind of lock in place is the fact that one of the original Chinese logos still appears on boot. Flashing a custom ROM should remove all the stock boot logos.

I get exactly the same error when trying to update the baseband with Odin (I tried several basebands and all had exactly the same error as the one you quoted in your first post), so it seems that what we have here is a baseband lock combined with an incompatibility between the existing baseband and the custom ROM (or, more likely, any ROM that isn't the stock ROM provided by China Unicom). If we can remove the baseband lock and update the baseband to one that is compatible with the custom ROM, we should be in business. Sadly, that's as far as I've got.

The annoying thing is that the SIM cards being used on the phone are both China Unicom, so it's not as if I even need the phone to be factory unlocked for use on any network - I simply need it to be able to make outgoing calls/texts on Unicom!

I have seen sites offering an unlock service by IMEI, for example unlocksamsungonline.com, who claim to provide both NCK (network unlock codes) and SPCK (service provider unlock codes), which seem to be what we need in order to unlock the phone without expensive equipment.

However, I have no idea how genuine/reliable these kinds of sites are or if they even work at all (or if they're even legitimate at all), and I'd rather not spend $18.95 USD on an unlock code that doesn't end up working. Also, given that it's a dual SIM phone it's going to have 2 IMEI numbers, so I'm not sure if I'd have to pay double to unlock it or if just one would do the trick!

I've not yet had the time to take the phone to an electronics market in the hope that somebody there understands the issue and has the equipment to remove the baseband lock. In almost all of my previous experiences with electronic markets here in Shanghai, I've found that their hardware knowledge is fantastic (not surprising given that the phones are made in China), but their software knowledge is generally quite poor. I actually spent almost an hour one day explaining to an iPhone engineer that he could in fact upgrade an iPhone's software while preserving an (unlockable) baseband, simply by making a custom ISPW with Pwnagetool or similar that would flash the new firmware without flashing the baseband. He and several of his coworkers claimed that it was impossible, and when I showed them my iPhone that was running the updated iOS while still on an old baseband, until I managed to explain the entire process he thought I had hacked the phone somehow to display a different baseband version... the whole experience was incredibly frustrating and to be honest has left me thinking that I can probably find out more online whenever I've had any kind of software issues with any devices.

Anyway. If you happen to have some success before I do, please let me know! I'll do the same.