Just different versions for different carriers and the different parts of the world.
so technically they are the same phone/hardware but different coding numbers or maybe different power plug options for different parts of the world. am i right?
They're 4 different phones with 4 different looks and sets of specs. You'll have to look up the specs on Nokia's site. In the US the 920 and 820 are on AT&T and the 822 is on Verizon. Not sure offhand where the 821 resides.
Found this somewhere:
RM-821: Global variant: EGSM 850/900/1800/1900, WCDMA 850/900/1900/2100, LTE band 1 (2100), 3 (1800), 7 (2600), 8 (900) & 20 (800), LTE Cat 3 (100 Mbps Downlink, 50 Mbps Uplink), HSDPA+ Cat24 (42.1 Mbps), HSUPA Cat 6 (5.76 Mbps)
RM-820: AT&T variant: EGSM 850/900/1800/1900, WCDMA 850/900/1900/2100, LTE band 2 (1900), 4 (1700/2100), 5 (850) & 17 (700), LTE Cat 3 (100 Mbps Downlink, 50 Mbps Uplink), HSDPA+ Cat24 (42.1 Mbps), HSUPA Cat 6 (5.76 Mbps)
I had to dig up this thread as I was looking at Navifirm and the number of versions each of these products have, I had a question : Has a RM-821 owner flashed RM-820? Does it happen successfully? Does it change? Does it brick?
...and another question:
Can RM-821 user flash any of the unlocked versions out there? i.e. EE, UK customer being able to flash Orange, France version?
So, if I flashed RM-821 on a RM-820 (AT&T), will the specs change to the global variant or it's just the software installed but still RM-820 frequencies?
I wonder know too...
I really want to do it, but I'm afraid.. hehehe