On this page, we have managed to share the Android 4.2.2 Stock ROM (Original firmware) for Samsung Galaxy Mega 6.3 I9200 Smartphone.
In case you were looking for the original firmware then this page might help you out.
Samsung Galaxy Mega 6.3 I9200 Stock ROM for Afghanistan
Model: GT-I9200
Country: Afghanistan
Version: Android 4.2.2
Changelist: 651213
Build date: Mon, 27 May 2013 16:20:24 +0000
Product Code: AFG
PDA: I9200XXUAMED
CSC: I9200OJVAME4
MODEM: I9200XXUAMED
Galaxy Mega 6.3 I9200 Stock ROM for Brazil
Model: GT-I9200
Country: Brazil
Version: Android 4.2.2
Changelist: 1716257
Build date: Fri, 20 Sep 2013 14:50:30 +0000
Product Code: ZTO
PDA: I9200UBUAMI2
CSC: I9200ZTOAMI2
MODEM: I9200UBUAMH2
Samsung Galaxy Mega 6.3 I9200 Stock ROM for Chile
Model: GT-I9200
Country: Chile
Version: Android 4.2.2
Changelist: 682252
Build date: Fri, 17 May 2013 03:15:31 +0000
Product Code: CHO
PDA: I9200UBUAME5
CSC: I9200UUBAME5
MODEM: I9200UBUAME5
Samsung Galaxy Mega 6.3 I9200 Stock ROM for China
Model: GT-I9200
Country: China
Version: Android 4.2.2
Changelist: 1646130
Build date: Mon, 16 Sep 2013 11:19:37 +0000
Product Code: CHU
PDA: I9200ZNUAMI2
CSC: I9200CHUAMI2
MODEM: I9200ZNUAMI2
Model: GT-I9200
Country: China
Version: Android 4.2.2
Changelist: 705790
Build date: Fri, 21 Jun 2013 07:28:41 +0000
Product Code: CHN
PDA: I9200ZCUAMF4
CSC: I9200CHNAMF4
MODEM: I9200ZCUAMF4
Galaxy Mega 6.3 I9200 Stock ROM for Egypt
Model: GT-I9200
Country: Egypt
Version: Android 4.2.2
Changelist: 651213
Build date: Mon, 27 May 2013 16:20:24 +0000
Product Code: EGY
PDA: I9200XXUAMED
CSC: I9200OJVAME4
MODEM: I9200XXUAMED
Samsung Galaxy Mega 6.3 I9200 Stock ROM for India
Model: GT-I9200
Country: India
Version: Android 4.2.2
Changelist: 651213
Build date: Wed, 22 May 2013 12:42:57 +0000
Product Code: INU
PDA: I9200DDUAME3
CSC: I9200ODDAME8
MODEM: I9200XXUAMEA
Model: GT-I9200
Country: India
Version: Android 4.2.2
Changelist: N/A
Product Code: INS
PDA: I9200DDUCNB1
CSC: I9200ODDCNB1
MODEM: I9200DDUCNB1
Galaxy Mega 6.3 I9200 Stock ROM for Indonesia
Model: GT-I9200
Country: Indonesia
Version: Android 4.2.2
Changelist: 651213
Build date: Tue, 28 May 2013 01:50:36 +0000
Product Code: XSE
PDA: I9200XXUAMEE
CSC: I9200OLBAME9
MODEM: I9200XXUAMEE
Samsung Galaxy Mega 6.3 I9200 Stock ROM for Iraq
Model: GT-I9200
Country: Iraq
Version: Android 4.2.2
Changelist: 651213
Build date: Mon, 27 May 2013 16:20:24 +0000
Product Code: MID
PDA: I9200XXUAMED
CSC: I9200OJVAME4
MODEM: I9200XXUAMED
Galaxy Mega 6.3 I9200 Stock ROM for Kazakhstan
Model: GT-I9200
Country: Kazakhstan
Version: Android 4.2.2
Changelist: 1858868
Build date: Fri, 11 Oct 2013 05:16:49 +0000
Product Code: SKZ
PDA: I9200XXUBMJ2
CSC: I9200OXEBMJ1
MODEM: I9200XXUBMJ2
Samsung Galaxy Mega 6.3 I9200 Stock ROM for Morocco
Model: GT-I9200
Country: Morocco
Version: Android 4.2.2
Changelist: 651213
Build date: Thu, 01 Aug 2013 12:49:40 +0000
Product Code: FWD
PDA: I9200XXUAMH1
CSC: I9200OJVAMH1
MODEM: I9200XXUAMED
Samsung Galaxy Mega 6.3 I9200 Stock ROM for Pakistan
Model: GT-I9200
Country: Pakistan (PAK)
Version: Android 4.2.2
Changelist: 651213
Build date: Mon, 27 May 2013 16:20:24 +0000
Product Code: PAK
PDA: I9200XXUAMED
CSC: I9200OJVAME4
MODEM: I9200XXUAMED
Samsung Galaxy Mega 6.3 I9200 Stock ROM for Panama
Model: GT-I9200
Country: Panama
Version: Android 4.2.2
Changelist: 682252
Build date: Fri, 17 May 2013 03:15:31 +0000
Product Code: TPA
PDA: I9200UBUAME5
CSC: I9200UUBAME5
MODEM: I9200UBUAME5
Model: GT-I9200
Country: Panama (Claro)
Version: Android 4.2.2
Changelist: 1524254
Build date: Wed, 28 Aug 2013 08:09:02 +0000
Product Code: CPA
PDA: I9200UBUAMH2
CSC: I9200UWAAMH2
MODEM: I9200UBUAMH2
Download ROM for Panama (Claro)
Galaxy Mega 6.3 I9200 Stock ROM for Puerto Rico
Model: GT-I9200
Country: Puerto Rico
Version: Android 4.2.2
Changelist: 1524254
Build date: Wed, 28 Aug 2013 08:09:02 +0000
Product Code: PCT
PDA: I9200UBUAMH2
CSC: I9200UWAAMH2
MODEM: I9200UBUAMH2
Samsung Galaxy Mega 6.3 I9200 Stock ROM for Russia
Model: GT-I9200
Country: Russia
Version: Android 4.2.2
Changelist: 1858868
Build date: Fri, 11 Oct 2013 05:16:49 +0000
Product Code: SER
PDA: I9200XXUBMJ2
CSC: I9200SERBMJ1
MODEM: I9200XXUBMJ2
Galaxy Mega 6.3 I9200 Stock ROM for Saudi Arabia
Model: GT-I9200
Country: Saudi Arabia
Version: Android 4.2.2
Changelist: 651213
Build date: Mon, 27 May 2013 16:20:24 +0000
Product Code: KSA
PDA: I9200XXUAMED
CSC: I9200OJVAME4
MODEM: I9200XXUAMED
Galaxy Mega 6.3 I9200 Stock ROM for Singapore
Model: GT-I9200
Country: Singapore
Version: Android 4.2.2
Changelist: 651213
Build date: Tue, 28 May 2013 01:50:36 +0000
Product Code: XSP
PDA: I9200XXUAMEE
CSC: I9200OLBAME9
MODEM: I9200XXUAMEE
Galaxy Mega 6.3 I9200 Stock ROM for Taiwan
Model: GT-I9200
Country: Taiwan
Version: Android 4.2.2
Changelist: 833838
Build date: Tue, 09 Jul 2013 09:39:24 +0000
Product Code: BRI
PDA: I9200ZTUAMG1
CSC: I9200ZZTAMG1
MODEM: I9200ZTUAMG1
Galaxy Mega 6.3 I9200 Stock ROM for Thailand
Model: GT-I9200
Country: Thailand
Version: Android 4.2.2
Changelist: 651213
Build date: Tue, 28 May 2013 01:50:36 +0000
Product Code: THL
PDA: I9200XXUAMEE
CSC: I9200OLBAME9
MODEM: I9200XXUAMEE
Galaxy Mega 6.3 I9200 Stock ROM for Trinidad and Tobago
Model: GT-I9200
Country: Trinidad and Tobago
Version: Android 4.2.2
Changelist: 682252
Build date: Fri, 17 May 2013 03:15:31 +0000
Product Code: TTT
PDA: I9200UBUAME5
CSC: I9200UUBAME5
MODEM: I9200UBUAME5
Download ROM for Trinidad and Tobago
Galaxy Mega 6.3 I9200 Stock ROM for Turkey
Model: GT-I9200
Country: Turkey
Version: Android 4.2.2
Changelist: 651213
Build date: Mon, 27 May 2013 16:20:24 +0000
Product Code: TUR
PDA: I9200XXUAMED
CSC: I9200OJVAME4
MODEM: I9200XXUAMED
Galaxy Mega 6.3 I9200 Stock ROM for Ukraine (Kyivstar)
Model: GT-I9200
Country: Ukraine (Kyivstar)
Version: Android 4.2.2
Changelist: 1858868
Build date: Fri, 11 Oct 2013 05:16:49 +0000
Product Code: SEK
PDA: I9200XXUBMJ2
CSC: I9200OXEBMJ1
MODEM: I9200XXUBMJ2
Download ROM for Ukraine (Kyivstar)
Galaxy Mega 6.3 I9200 Stock ROM for United Arab Emirates
Model: GT-I9200
Country: United Arab Emirates
Version: Android 4.2.2
Changelist: 651213
Build date: Mon, 27 May 2013 16:20:24 +0000
Product Code: XSG
PDA: I9200XXUAMED
CSC: I9200OJVAME4
MODEM: I9200XXUAMED
Download ROM for United Arab Emirates
Galaxy Mega 6.3 I9200 Stock ROM for Uzbekistan
Model: GT-I9200
Country: Uzbekistan
Version: Android 4.2.2
Changelist: N/A
Build date: Thu, 01 Jan 1970 00:00:00 +0000
Product Code: CAC
PDA: I9200XXUBMJ2
CSC: I9200OXEBMJ1
MODEM: I9200XXUBMJ2
Galaxy Mega 6.3 I9200 Stock ROM for Vietnam
Model: GT-I9200
Country: Vietnam
Version: Android 4.2.2
Changelist: 651213
Build date: Tue, 28 May 2013 01:50:36 +0000
Product Code: XXV
PDA: I9200XXUAMEE
CSC: I9200OLBAME9
MODEM: I9200XXUAMEE
Notes
[*] How to flash Galaxy Mega 6.3 Stock ROM: Download the ROM then see Flash Samsung Stock ROM.
[*] Samsung Galaxy Mega USB Driver: If you are looking for the USB Driver, then head over to the Samsung USB Driver page.
[*] Stuck at Boot loop: If your Samsung Galaxy Mega 6.3 stuck at boot after downgrading then Boot your smartphone into recovery mode and Wipe Data and Cache.
[*] How to root: If you want to root Samsung Galaxy Mega 6.3 then head over to root Samsung Galaxy Mega 6.3.