How to change the lock screen image on Ledger Flex? (Customization)

Understanding Ledger Flex Lock Screen Fundamentals

1. The Ledger Flex device features a 3.7-inch E Ink touchscreen that supports custom lock screen images, unlike earlier models with fixed branding or minimal visual feedback.

2. Custom lock screen images are stored locally on the device’s secure microSD card slot and rendered only after successful PIN verification—no image data is transmitted to Ledger Live or external servers.

3. Supported formats include PNG and JPEG with dimensions strictly capped at 360×360 pixels and file size limited to 256 KB. Exceeding either constraint results in silent rejection during upload.

4. Image rendering occurs in monochrome grayscale due to the E Ink display’s physical limitations; color information is automatically dithered during conversion without user control.

5. Each uploaded image replaces the previous one—Ledger Flex does not support slideshow or rotation between multiple lock screen assets.

Preparing Your Custom Image File

1. Use vector-to-raster tools such as Inkscape or Adobe Illustrator to design artwork at exact 360×360 resolution before exporting to PNG.

2. Avoid anti-aliased text smaller than 14pt—E Ink’s low refresh rate and lack of backlight cause fine details to appear blurred or illegible upon wake-up.

3. Apply a 2-pixel black border around critical UI elements (e.g., wallet name placeholder, asset icon zone) to ensure contrast against ambient light conditions.

4. Save with sRGB color profile and disable embedded ICC profiles—non-standard profiles trigger automatic discarding by Ledger’s firmware parser.

5. Verify file integrity using command-line tools: file your_image.png must return “PNG image data, 360 x 360, 8-bit/color RGB, non-interlaced”.

Uploading via Ledger Live Desktop Application

1. Launch Ledger Live version 2.42.0 or higher on Windows/macOS/Linux; ensure Bluetooth is disabled to force USB-C communication path.

2. Connect Ledger Flex using the included USB-C cable and unlock with correct PIN—device must be in idle state, not inside an app.

3. Navigate to Settings → Device → Appearance → Lock screen image → Choose file.

4. Select your validated PNG/JPEG file; Ledger Live performs local checksum validation before initiating transfer.

5. Wait for the green checkmark confirmation on both Ledger Live interface and Flex screen—interrupting this process may brick the display firmware partition.

Direct MicroSD Card Injection Method

1. Format a microSD card to FAT32 with MBR partition scheme; exFAT or GPT cards will not mount on Flex firmware.

2. Create a root-level folder named /ledger/lockscreen/ and place exactly one image file inside, named lock.png or lock.jpg.

3. Insert the card into Flex’s tray while powered off; power on and hold both side buttons for 7 seconds until haptic pulse confirms recognition.

4. Navigate to Settings → Device → Appearance → Lock screen image → Refresh from SD—this bypasses Ledger Live entirely.

5. Confirm activation by locking the device manually (press and hold power button); the new image must render within 1.2 seconds.

Frequently Asked Questions

Q: Does changing the lock screen affect transaction signing security?A: No. Lock screen customization resides entirely outside the Secure Element and does not influence cryptographic operations or private key exposure pathways.

Q: Can I use animated GIFs or WebP files?A: No. Firmware only parses static PNG and JPEG. Attempting to load WebP triggers immediate “Invalid format” error; GIFs are ignored without notification.

Q: Why does my image appear vertically stretched on the Flex screen?A: This indicates incorrect aspect ratio handling during export. Ensure canvas dimensions are precisely 360×360—not 360×640 or scaled from smartphone screenshots.

Q: Is there a way to revert to the default Ledger logo lock screen?A: Yes. In Ledger Live, go to Settings → Device → Appearance → Lock screen image → click “Reset to default”. No microSD card action required.