[Galaxy S III Q&A, Help & Troubleshooting] moviedrome:
Hi, I'm sorry if this is a really dumb question. I'm trying to flash the O2 specific modem onto my Galaxy S3 which currently has the stock XXEMG4 firmware (and modem on it)

I initially tried the following command:

heimdall flash --modem modem.bin

and it tells me that the Partition modem doesn't exist

okay, so I've printed the PIT and it tells me the partition is called radio. I found an issue where they said they added the flag --radio and so I tried:

heimdall flash --radio modem.bin

This is my result:

Heimdall v1.4.0

Copyright (c) 2010-2013, Benjamin Dobell, Glass Echidna

This software is provided free of charge. Copying and redistribution is
encouraged.

If you appreciate this software and you would like to support future
development please consider donating:

Initialising connection...
Detecting device...
Claiming interface...
Setting up interface...

Initialising protocol...
Protocol initialisation successful.

Beginning session...

Some devices may take up to 2 minutes to respond.
Please be patient!

Session begun.

Downloading device's PIT file...
PIT file download successful.

ERROR: Partition "radio" does not exist in the specified PIT.
Ending session...
Rebooting device...
Releasing device interface...

Print-pit gives the following:

Downloading device's PIT file...
PIT file download successful.

Entry Count: 16
Unknown 1: 1598902083
Unknown 2: 844251476
Unknown 3: 30797
Unknown 4: 0
Unknown 5: 0
Unknown 6: 0
Unknown 7: 0
Unknown 8: 0

--- Entry #0 ---
Binary Type: 0 (AP)
Device Type: 2 (MMC)
Identifier: 80
Attributes: 2 (STL Read-Only)
Update Attributes: 1 (FOTA)
Partition Block Size/Offset: 0
Partition Block Count: 1734
File Offset (Obsolete): 0
File Size (Obsolete): 0
Partition Name: BOOTLOADER
Flash Filename: sboot.bin
FOTA Filename:

--- Entry #1 ---
Binary Type: 0 (AP)
Device Type: 2 (MMC)
Identifier: 81
Attributes: 5 (Read/Write)
Update Attributes: 1 (FOTA)
Partition Block Size/Offset: 1734
Partition Block Count: 312
File Offset (Obsolete): 0
File Size (Obsolete): 0
Partition Name: TZSW
Flash Filename: tz.img
FOTA Filename:

--- Entry #2 ---
Binary Type: 0 (AP)
Device Type: 2 (MMC)
Identifier: 70
Attributes: 5 (Read/Write)
Update Attributes: 1 (FOTA)
Partition Block Size/Offset: 34
Partition Block Count: 16
File Offset (Obsolete): 0
File Size (Obsolete): 0
Partition Name: PIT
Flash Filename: mx.pit
FOTA Filename:

--- Entry #3 ---
Binary Type: 0 (AP)
Device Type: 2 (MMC)
Identifier: 71
Attributes: 5 (Read/Write)
Update Attributes: 1 (FOTA)
Partition Block Size/Offset: 50
Partition Block Count: 2048
File Offset (Obsolete): 0
File Size (Obsolete): 0
Partition Name: MD5HDR
Flash Filename: md5.img
FOTA Filename:

--- Entry #4 ---
Binary Type: 0 (AP)
Device Type: 2 (MMC)
Identifier: 1
Attributes: 5 (Read/Write)
Update Attributes: 1 (FOTA)
Partition Block Size/Offset: 8192
Partition Block Count: 8192
File Offset (Obsolete): 0
File Size (Obsolete): 0
Partition Name: BOTA0
Flash Filename: -
FOTA Filename:

--- Entry #5 ---
Binary Type: 0 (AP)
Device Type: 2 (MMC)
Identifier: 2
Attributes: 5 (Read/Write)
Update Attributes: 1 (FOTA)
Partition Block Size/Offset: 16384
Partition Block Count: 8192
File Offset (Obsolete): 0
File Size (Obsolete): 0
Partition Name: BOTA1
Flash Filename: -
FOTA Filename:

--- Entry #6 ---
Binary Type: 0 (AP)
Device Type: 2 (MMC)
Identifier: 3
Attributes: 5 (Read/Write)
Update Attributes: 5 (FOTA)
Partition Block Size/Offset: 24576
Partition Block Count: 40960
File Offset (Obsolete): 0
File Size (Obsolete): 0
Partition Name: EFS
Flash Filename: efs.img
FOTA Filename:

--- Entry #7 ---
Binary Type: 0 (AP)
Device Type: 2 (MMC)
Identifier: 4
Attributes: 5 (Read/Write)
Update Attributes: 1 (FOTA)
Partition Block Size/Offset: 65536
Partition Block Count: 16384
File Offset (Obsolete): 0
File Size (Obsolete): 0
Partition Name: PARAM
Flash Filename: param.bin
FOTA Filename:

--- Entry #8 ---
Binary Type: 0 (AP)
Device Type: 2 (MMC)
Identifier: 5
Attributes: 5 (Read/Write)
Update Attributes: 1 (FOTA)
Partition Block Size/Offset: 81920
Partition Block Count: 16384
File Offset (Obsolete): 0
File Size (Obsolete): 0
Partition Name: BOOT
Flash Filename: boot.img
FOTA Filename:

--- Entry #9 ---
Binary Type: 0 (AP)
Device Type: 2 (MMC)
Identifier: 6
Attributes: 5 (Read/Write)
Update Attributes: 1 (FOTA)
Partition Block Size/Offset: 98304
Partition Block Count: 16384
File Offset (Obsolete): 0
File Size (Obsolete): 0
Partition Name: RECOVERY
Flash Filename: recovery.img
FOTA Filename:

--- Entry #10 ---
Binary Type: 0 (AP)
Device Type: 2 (MMC)
Identifier: 7
Attributes: 5 (Read/Write)
Update Attributes: 1 (FOTA)
Partition Block Size/Offset: 114688
Partition Block Count: 65536
File Offset (Obsolete): 0
File Size (Obsolete): 0
Partition Name: RADIO
Flash Filename: modem.bin
FOTA Filename:

--- Entry #11 ---
Binary Type: 0 (AP)
Device Type: 2 (MMC)
Identifier: 8
Attributes: 5 (Read/Write)
Update Attributes: 5 (FOTA)
Partition Block Size/Offset: 180224
Partition Block Count: 2097152
File Offset (Obsolete): 0
File Size (Obsolete): 0
Partition Name: CACHE
Flash Filename: cache.img
FOTA Filename:

--- Entry #12 ---
Binary Type: 0 (AP)
Device Type: 2 (MMC)
Identifier: 9
Attributes: 5 (Read/Write)
Update Attributes: 5 (FOTA)
Partition Block Size/Offset: 2277376
Partition Block Count: 3145728
File Offset (Obsolete): 0
File Size (Obsolete): 0
Partition Name: SYSTEM
Flash Filename: system.img
FOTA Filename:

--- Entry #13 ---
Binary Type: 0 (AP)
Device Type: 2 (MMC)
Identifier: 10
Attributes: 5 (Read/Write)
Update Attributes: 5 (FOTA)
Partition Block Size/Offset: 5423104
Partition Block Count: 1146880
File Offset (Obsolete): 0
File Size (Obsolete): 0
Partition Name: HIDDEN
Flash Filename: hidden.img
FOTA Filename:

--- Entry #14 ---
Binary Type: 0 (AP)
Device Type: 2 (MMC)
Identifier: 11
Attributes: 5 (Read/Write)
Update Attributes: 1 (FOTA)
Partition Block Size/Offset: 6569984
Partition Block Count: 16384
File Offset (Obsolete): 0
File Size (Obsolete): 0
Partition Name: OTA
Flash Filename: -
FOTA Filename:

--- Entry #15 ---
Binary Type: 0 (AP)
Device Type: 2 (MMC)
Identifier: 12
Attributes: 5 (Read/Write)
Update Attributes: 5 (FOTA)
Partition Block Size/Offset: 6586368
Partition Block Count: 0
File Offset (Obsolete): 0
File Size (Obsolete): 0
Partition Name: USERDATA
Flash Filename: userdata.img
FOTA Filename: remained

So entry 10 clearly says radio, any ideas what i'm doing wrong?

Also probably not the place to ask but while I'm here - is it okay to just flash a radio, I don't want to root or change anything else, just change the modem to try and improve the crap signal O2 give me