How to update software BMW MK4 navigation + add custom splash image

This guide shows how to replace the default BMW logo on your MK4 Professional Navigation with a custom image such as your own car, M-power logo, or any 400×234 pixel design. Based on real-world E46 Touring 2005 project using community-modified firmware.

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Used tool in this guide

(Optional: I’ve used it to set radio in update state and confirm it is MK4 navi but you don’t need it for this)

How to verify you have MK4

Supported models: E46 / E39 / E38 / E53 / E83 / E85 / E86 with MK4 navi

Before starting, confirm you have MK4 by checking:

1. Location: Nav computer in trunk (not dashboard)
2. Front panel: “DVD” logo visible
3. Eject button: Round shape
4. Part number: Starts with 65 and has 69XX XXX format
5. Software: Settings menu shows MK4 version (SW 1-X/XX to 4-X/XX)

If you have MK2 (CD) or MK3 (CD) — this procedure will not work.
If you have iDrive (E60, E65, E90+) — this procedure will not work.

If you have MK3 (looks same but doesn’t have DVD logo -> you can just swap for MK4 plug and play)

Video: How to update firmware in bmw mk4 navi + custom image

This video shows how to

Technical overview

Item	Details
Vehicle	BMW E46 Touring
Year	2005
System	MK4 Navigation (DVD-based)
Procedure type	Firmware modification/update + custom splash
Difficulty	Advanced
Time required	~60 minutes
Prerequisites	Windows laptop with CD slot or external CD machine, clean DVD-R for burning

Step-by-step procedure

Step 1: Download MK4 v32 firmware

The easiest path — just update to the latest official v32 firmware without custom splash modification.

Download:

• MK4 v32 firmware ISO — [download link]
• ImgBurn (free DVD burning software) — imgburn.com

If you only want to update firmware → skip to Step 6 (Burn to DVD).

If you want a custom splash image on your dashboard → continue with Optional Steps 2-5.

Optional Steps – Custom Splash Image

Follow these steps only if you want to replace the default BMW logo with your own image.

Optional Step 1: Download required software

Software	Purpose	Link
UltraISO	Open and edit ISO files	ezbsystems.com
NavTweak 2.6	Edit MK4 navboot file	[download link]
GTK+ 2.12.9 Runtime	Required for NavTweak to run	sourceforge.net

💡 Pro tip: Install GTK+ runtime before launching NavTweak — otherwise NavTweak won’t start.

Optional Step 2: Prepare your custom splash image

Your image must meet these exact specifications:

Parameter	Value
Dimensions	400 × 234 pixels
Format	GIF (indexed color)
Color depth	16 colors (for smallest file size)
File size	Under 8,000 bytes (critical!)
Animation	Single frame only

Easiest method — use ChatGPT or Claude:

Instead of learning Photoshop or Photopea, just use AI to prepare your image. Upload your source photo and use this prompt:

Resize this image to exactly 400×234 pixels, convert to indexed GIF with
16 colors maximum, no dither, no transparency. The final file must be
under 8000 bytes. Return the GIF file for download.

Works with: ChatGPT (with image tools), Claude, or any AI image tool.

⚠️ Warning: Files larger than 8KB will cause silent flash failures. Stay close to the original BMW splash size of ~7,952 bytes.

Optional Step 3: Locate navboot file in the ISO

1. Open UltraISO (run as administrator)
2. File → Open → select MK4_v32.iso
3. Navigate to this exact path inside the ISO:

V_2 / RR / 0101 / BMWC01S / app_sw / navboot

4. Right-click navboot → Extract to…
5. Save to a working folder, e.g. C:\BMW_NAV\original\navboot

✅ Success indicator: You should now have the navboot file on your local disk.

![UltraISO navboot location screenshot]

Optional Step 4: Replace splash image in navboot

1. Launch NavTweak (with GTK runtime installed)
2. File → Open → select your extracted navboot file
3. Click the Images tab
4. Expand rombitmaps section
5. Scroll to line 14 — this is the main BMW splash image (400×234 GIF)
6. Right-click line 14 → Replace
7. Select your custom GIF prepared in Step 2
8. Verify the preview shows your new image

![NavTweak line 14 replacement screenshot]

Only replace line 14. Other entries control different system graphics. If you want you can replace those as well for more customizations.

Optional Step 5: Save modified navboot to ISO

1. In NavTweak: File → Save the modified navboot (overwrite original location or save as new)
2. Switch back to UltraISO with the v32 ISO still open
3. Navigate to V_2 / RR / 0101 / BMWC01S / app_sw /
4. Drag and drop your modified navboot into the right panel
5. Confirm Overwrite? → Yes
6. File → Save As → MK4_v32_custom.iso
7. Choose ISO Image File format when saving

✅ Success indicator: New ISO file is created with your modified navboot embedded.

⚠️ Extra Step If You Already Have v32 Installed

If your navigation is already running v32 firmware (check in Settings), it will reject the same-version update with a “Software is up to date” message.

Option A: Downgrade, then upgrade with custom splash

You’ll need to downgrade to an older version first, then flash your custom v32 on top. You can find older versions here: http://www.e38.org/nav/

Process:

1. Burn older version (v29 recommended) → flash it
2. After downgrade completes → burn your custom v32 ISO → flash
3. Nav accepts upgrade from v29 → v32 with your custom splash

Option B (Members only) – Community custom V32

Members get access to a custom v32 ISO that bypasses the same-version check completely. No downgrade required — flash your custom splash directly over existing v32.

[🔒 Become a Member for v32.3 ISO access]

💡 Pro tip: Community v32 contains the same firmware as v32 but with modified version tags that pass MK4 checksum validation.

Step 6: Burn custom ISO to DVD

DVD media choice is critical – MK4 is picky about which discs it reads.

Required DVD specifications:

Parameter	Value
Type	DVD-R only (NOT DVD+R!)
Capacity	4.7 GB (single layer)
Brand	Verbatim AZO (highest compatibility)
Speed rating	16x max (we burn at 4x)

❌ DO NOT USE:

• DVD+R discs (rejected by MK4)
• Dual layer discs
• Rewriteable (DVD-RW) discs
• No-name brand discs
• Re-used discs

Burning process:

1. Insert fresh Verbatim DVD-R into PC burner
2. Open ImgBurn
3. Click “Write image file to disc”
4. Source: your custom ISO file
5. Configure settings:
   • Write Speed: 4x (slower = more reliable)
   • Verify: ON ✅
   • Copies: 1
6. Click Burn
7. Wait 8-10 minutes for burn + verify

✅ Success indicator: ImgBurn shows “Operation Successfully Completed!”

Step 7: Flash DVD in the vehicle

Critical: The DVD must go in the navigation computer in the trunk NOT the CD slot in the radio!

Vehicle location of nav computer:

• E46 Sedan/Coupe/Touring: Right side of trunk behind panel
• E39: Left side of trunk
• E38: Trunk, right side
• E53 X5: Rear cargo area, right side
• E83 X3: Rear cargo area

Vehicle preparation: power is critical:

Most guides say “ignition ON, doors open”. Here’s what actually works and keeps your nav safe:

✅ Engine RUNNING (recommended if battery is weak or older) ✅ Doors OPEN (prevents sleep mode) ✅ Headlights OFF (reduces electrical load)

⚠️ Most important rule: Do NOT turn off ignition during flash!

Whether you choose ignition ON or engine running — just keep power stable for the entire flash duration.

💡 Real-world tip: On my E46 Touring 2005 with an older battery, flashing with ignition ON alone caused voltage drops during the flash process. Running the engine ensured stable 14V from the alternator and the flash completed without issues.

Flashing the DVD:

1. Open trunk, locate nav computer
2. Press eject button → remove existing map DVD (if any)
3. Insert your custom firmware DVD
4. Start engine (or ignition ON if battery is healthy)
5. Turn on ignition if not already
6. Display shows: “Software Update — will update your Navigation System!”
7. Screen warns: “Up to 6 minutes. Do not turn off ignition during installation!”
8. Confirm update
9. Wait untill it finish – do not touch anything
10. DVD ejects automatically when complete
11. Nav reboots with your firmware (and custom splash if applied!)

⚠️ DO NOT during flash:

• ❌ Turn off engine or ignition
• ❌ Open/close hood
• ❌ Press buttons on dashboard
• ❌ Eject DVD manually
• ❌ Use electrical accessories (A/C, wipers, etc.)

✅ Success indicator: Nav reboots and shows your custom image (or BMW logo if firmware-only update) at every startup.

Additional Information & Compatibility Notes

Before using or purchasing any diagnostic tool for this procedure, always verify compatibility with your exact vehicle model, year and system configuration. Supported functions may vary depending on software version, hardware revision and regional limitations.

Legal & safety notice

This procedure modifies vehicle system settings through the control module. Incorrect use may cause faults or warning lights. Always ensure the vehicle is secured and follow proper safety procedures.

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