This program is an utility to manipulate Garmin RGN/GCD firmware files. It allows you to:
  • Convert GCD or RGN firmware files to RGN or GCD format;
  • Extract and save the individual firmware sections of RGN/GCD files to .bin files;
  • Overwrite HWID and SW Version of RGN/GCD;
  • Build an RGN or GCD file using different .bin files.
  • Automatically re-order the sections for compatibility with GCD or RGN files (single boot files)

Official disclaimers:
  • Do this at your own risks!
  • Do not flash any FW if you are getting weird errors

Screen Shots



1- Convert GCD to RGN
  • File->Open and select your GCD file
  • File->Save to RGN and select the RGN file name.
  • Remove any previous GUPDATE.GCD file from your GPS before flashing
  • Flash in pre-boot/service mode using updater.exe from Garmin

2- Convert RGN to GCD
  • File->Open and select your RGN file
  • File->Save to GCD and select the GCD file name.
  • Rename or copy GUPDATE.GCD to your GPS. Reboot.
Note: the GPS may not update the firmware is the SW Version in the GCD is exactly the same as the one already on the GPS.

3- Convert to TWN firmware from US gps units
  • File->Open and select your US firmware GCD or RGN file
  • Click the Save button in the boot.bin section (the first on top) and save it to boot_us.bin
  • File->Open and select your TWN firmware GCD or RGN file
  • Click the Load button in the boot.bin section (the first on top) and load boot_us.bin (the one you saved in previous step)
  • Notice the HWID and SW Version from this boot.bin and copy those numbers in the Overrides section. Enable the checkboxes and put the numbers from boot.bin.
  • File->Save to RGN (or to GCD) and select the RGN (or GCD) file name.
  • If you are using RGN file, remove any previous GUPDATE.GCD file from your GPS before flashing
  • Flash RGN in pre-boot/service mode using updater.exe from Garmin, or copy GUPDATE.GCD to your GPS and reboot.

For support, you can post here or visit this thread:

Command-line Usage

The command-line options are only available in RGN_Tool v0.80 and above. It is intended for advanced users that want to do batch processing and conversions. Calling RGN_Tool without argument will call the default GUI interface.

Usage: RGN_Tool [-hwid id] [-swv ver] [-preserve | -nopreserve] [-replace | -noreplace] [file.rgn | file.gcd] [file.bin]1+ [-bin opath] | [-o [file.rgn | file.gcd]]

-hwid id : specifies the HWID used to overwrite existing HWID in the various firmware sections.
-swv ver : specifies the SW Version used to overwrite existing SWV in the various firmware sections.

-preserve : preserve the section number when saving to RGN
-nopreserve : re-order file sections when saving to RGN

-replace : replace HWID/SWVer text strings
-noreplace : do not replace HWID/SWVer text strings

-bin opath : extract all .bin files in the specfied opath folder. opath can be a relative or absolute path. Enclose with "" is there are spaces in the filepath. If -bin is used, RGN_Tool will terminate after saving the .bin files.

-o file : indicates following file name to save to. If used, RGN_Tool will terminate after saving to the file.

Example 1: Load the specified gcd or rgn in RGN_Tool

  • RGN_tool gupdate.gcd
  • RGN_tool nuvi_37xx_CHN_v250.rgn

Example 2: Load a bunch of .bin files in RGN_Tool. Overwrite hwid to 1101 and swv to 250.

  • RGN_tool -hwid 1101 -swv 250 boot_US_hwid_1101_v430.bin fw_all_CHN_hwid_1263_v250.bin resources_CHN_v250.bin

Example 3: Load a gcd, overwrite hwid to 1234, preserve the sections order, save to gupdate_mod.gcd and terminate RGN_Tool

  • RGN_Tool -hwid 1234 -preserve gupdate.gcd -o gupdate_mod.gcd

Example 4: Load an rgn file, extract .bin files in a test sub-folder and terminate RGN_Tool.

  • RGN_Tool nuvi_37xx_CHN_250.rgn -bin test
  • RGN_Tool gupdate.gcd -bin "c:\extract bin"
  • RGN_Tool gupdate.gcd -bin .

Many combinations are possible. I think you get the idea.


Latest version: RGN_Tool_v094.zip

  • If you want to see improvements made to this tool, please DONATE. See below:

Previous versions:

Revision History

  • Support for fw_all.bin file in fenix3HR and D2Bravo

  • Improved HWID and SWV detection.
  • Adding section names to .bin files (not used by RGN_Tool)

  • Added detection of sections 2B05 and 0505 for Approach S60 (fw_2B05.bin and fw_0505.bin) with HWID & SWV replacement

  • Added detection of sections 9505 (Tuner_RGN), 9905 (Audio_RGN) and partly 1B05 (all_fw3).
  • Added support for Approach S60 Golf watch & changed HWID in Bxxxx strings
  • More sections detection: TUNERRGN, AUDIORGN, Fonts.

  • Improved detection of pk_file66.zip for region 66

  • Added disk image detection when loading an fftl.bin type file and assigned region 0x30 by default for 34xx device. May be different for other model.

  • Fixed a runtime error when saving to .gcd (does not happen all the time)

  • Added a Nuvi 3790 Patch in the Tools menu. This will enable the Calendar, the Contacts and the ASR on the Nuvi 3770, 3760 and 3750. ASR is visible but not functional on the 3750 since no microphone installed. Tested and working for all 37xx Asian firmwares with nuvi 3750. Report problems to TurboCCC. On US firmwares, you can enable ASR on the 3760.

  • Added support for nuvi_8xxx rgn file with section 80 (0x50) virtual_image.bin extraction and packing back to .rgn.
  • Fixed another runtime error with missing file path when using drag & drop (don't ask, just update to this version)...

  • Added .bin file drag&drop in respective section.
  • Fixed various path issues when dragging files or starting RGN_Tool with a right click.
  • Added some missing 01 checksum sections between different firmware sections in GCD.

  • Added command-line support. Type "RGN_Tool ?" for details.
  • Added a default filename based on input file when saving RGN or GCD.

  • Set the RGN region to 0x10 for special gir file containing 24xx/23xx logo.

  • Set the RGN region to 0x10 for special gir file containing 37xx logo.

  • Fixed a bad detection between pk_file66.zip and pk_text.zip section when loading .zip file.

  • Improved string search. Everything should run faster.

  • Fixed a crash issue when searching for a non-existant HWID in a section 5505.

  • If a file is dragged over the RGN_Tool.exe or a file extension is registered to RGN_Tool, then the initial folder is set to the path of the file. This is very useful when right clicking on a GCD or RGN file and using "Open With".

  • Fixed a crash issue when the GCD contained garbage at the end of the file.
  • Added support for RGN region FF and PK/text zip file.

  • Added checkbox to preserve the .bin file order and disable auto re-order.
  • Added filename to command-line. You can drag gcd/rgn over RGN_Tool.exe to load or drag gcd/rgn file over the application to load. This allows you also to register .gcd or .rgn extensions to RGN_Tool which will invoke automatically RGN_Tool when double clicking on the gcd/rgn files.
  • You can also drag&drop rgn/gcd files over the opened instance of RGN_Tool.

  • Added "Replace HWID test strings" checkbox. When enabled, this will search sections 0800 (boot.bin) and BD02 (fw_all.bin) to see if it finds HWID text strings and replace them with the HWID override value. This checkbox is automatically enabled when you enable HWID override. This is required to have the proper HWID value in the Inventory display and in GarminDevices.xml. This will make sure Garmin sends the update firmware with the proper HWID to your GPS.


  • Fixed an issue where the HWID & SWV were not overridden in the GCD headers causing the GPS to reboot continuously.

  • Added "Save to GCD". Works for regular boot+fw_all[+resources] and other combinations with single boot.
  • Improved GCD parsing - no more guessing
  • Automatically puts region 0E (fw_all) to second section when saving to GCD.

  • Different search engine for GCD sections. Only supported sections will be detected. Now, it parses GpsMap GCD files without problems. Send me an email if the program crashes and a link to your file.
  • Detects also *some* HWID and SWV in 0104 sections.

  • Fixed checksum in fw_all section (only) after overrides.

  • Fixed an issue when saving RGN files with more than 2 sections.

Virus Report by VirusTotal

No, there is no virus in RGN_Tool. This is a false positive from some (bad) anti-virus. I have included below the virus report analysis by VirusTotal.com. As you can see, no serious anti-virus found any issue with RGN_Tool. If I use different compiler options, then suddenly I get 5 or 6 false positives out of 43 anti-virus. Be assured I would not post any files with a virus in it. Turbo.

Virustotal is a service that analyzes suspicious files and URLs and facilitates the quick detection of viruses, worms, trojans, and all kinds of malware detected by antivirus engines.

File name: RGN_Tool.exe
Submission date: 2011-02-11 00:53:23 (UTC)

Result: 1/ 41 (2.4%)

Compact Print results Antivirus Version Last Update Result
AhnLab-V3 2011.02.06.00 2011.02.06 -
AntiVir 2011.02.10 -
Antiy-AVL 2011.02.10 -
Avast 4.8.1351.0 2011.02.10 -
Avast5 5.0.677.0 2011.02.10 -
AVG 2011.02.10 -
BitDefender 7.2 2011.02.11 -
CAT-QuickHeal 11.00 2011.02.10 -
ClamAV 2011.02.10 -
Commtouch 2011.02.10 -
Comodo 7645 2011.02.10 -
DrWeb 2011.02.11 -
eSafe 2011.02.10 -
eTrust-Vet 36.1.8152 2011.02.10 -
F-Prot 2011.02.04 -
F-Secure 9.0.16160.0 2011.02.10 -
Fortinet 2011.02.10 -
GData 21 2011.02.10 -
Ikarus T3. 2011.02.10 -
Jiangmin 13.0.900 2011.02.10 Backdoor/Hupigon.bpty
K7AntiVirus 9.83.3813 2011.02.10 -
McAfee 5.400.0.1158 2011.02.11 -
McAfee-GW-Edition 2010.1C 2011.02.08 -
Microsoft 1.6502 2011.02.10 -
NOD32 5863 2011.02.10 -
Norman 6.07.03 2011.02.10 -
nProtect 2011-01-27.01 2011.02.02 -
Panda 2011.02.10 -
PCTools 2011.02.10 -
Prevx 3.0 2011.02.11 -
Rising 2011.02.10 -
Sophos 4.61.0 2011.02.10 -
SUPERAntiSpyware 2011.02.11 -
Symantec 20101.3.0.103 2011.02.11 -
TheHacker 2011.02.10 -
TrendMicro 2011.02.10 -
TrendMicro-HouseCall 2011.02.11 -
VBA32 2011.02.10 -
VIPRE 8376 2011.02.11 -
ViRobot 2011.2.10.4303 2011.02.11 -
VirusBuster 2011.02.10 -


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