Verified Firmware Update Procedures for the OSSC and RetroTINK Scaler Line

Your RetroTINK 5X is stuck on an old feature set. Your OSSC will not recognise a new console because its sampling phase table is out of date. The fix is the same physical action for both devices: put a file on a FAT32 microSD card, insert it, and boot the scaler into its update mode. The risk is a brick if the power drops during the ten to sixty seconds the update takes. Use a stable power source, not the USB port of a laptop that might go to sleep.

Firmware version numbers and feature lists are perishable. The OSSC stable release is 0.90 from 2023 and the experimental branch is 0.91 from the same year. The RetroTINK 5X Pro is at release 3.71 from 15 November 2024. The RetroTINK 4K is at release 1.6.3 from 10 March 2025, but that number is revised annually. Check the project's own site for the build in force on the day you read this. What matters is the procedure, which has not changed.

The OSSC firmware update tool is a microSD card, nothing else. There is no USB utility, no JTAG header required for routine updates. Format a card of 32 GB or less to FAT32. Download the .bin file from the OSSC GitHub Releases page. Place the file in the root directory of the card. Do not rename it. Power off the OSSC. Insert the card. Hold the BTN0 button while powering the unit on. The screen shows a progress bar. The update takes roughly ten seconds. When the bar completes, power cycle the scaler. Confirm the new release in the Information menu under the on-screen display.

The failure case is a power loss during the write. If that happens, the OSSC may appear bricked. Recovery is the same procedure: reinsert the card with the same file and repeat. If the card is larger than 32 GB or formatted as exFAT, the OSSC will not read it. Use a small card you keep dedicated to updates.

The OSSC Pro firmware upgrade follows the same microSD method as the original OSSC, with one difference: the Pro adds a framebuffer and adaptive line multiplication, so its firmware file is larger and the update takes longer, approximately thirty seconds. Hold the correct bootloader key combination as documented in the OSSC Pro wiki when you power on. The file extension is still .bin. Place it in the root of a FAT32 card of 32 GB or less.

The Pro firmware changelog lives on the same GitHub repository. A firmware upgrade may change the behaviour of the advanced timing tweaker, update the profile saving system, or alter how the scaler handles HDMI input for modern consoles. Read the changelog before updating so you know which settings defaults will reset.

Running The Update

The RetroTINK 5X firmware update is the most common procedure in the hobby because Mike Chi releases updates frequently. Release 3.71 from November 2024 is the current stable build. Download the .rbf file from the RetroTINK firmware page at retrotink-llc.github.io. Copy it to the root of a FAT32 microSD card of 32 GB or less. Power off the 5X. Insert the card. Power on. The scaler detects the file automatically and shows a progress bar on screen. The update takes about thirty seconds. When it finishes, power cycle the unit. Verify the build number in the OSD Info screen.

What Changes And How To Recover

A firmware update on the RetroTINK 5X can change the sampling phase defaults for specific consoles, add new CRT simulation filters, adjust the adaptive line multiplication behaviour, or import new FirebrandX profile presets. It may also update the EDID management for capture card compatibility. If you use DVI compatibility mode or TX mode for a particular display, check the changelog on the firmware site to see whether those settings changed. The RetroTINK 5X supports downgrade. If a release breaks something, repeat the procedure with an older .rbf file.

Power And Preparation

The RetroTINK 4K update process is identical in concept to the 5X but uses a USB-C PD power supply during the update. Do not power the 4K from a standard USB port. The scaler draws more current during the write, and a port that cannot deliver enough will cause a partial write that may require a reflash. Use the power supply that shipped with the unit or a 15W USB-C PD adapter.

Running The Update

Download the .rbf file from the RetroTINK 4K firmware page. Place it on a FAT32 microSD card of 32 GB or less. Power off. Insert card. Power on. The update takes roughly sixty seconds. The progress bar is on screen. Power cycle after completion.

Changelog And Profile Safety

The 4K firmware changelog is published at retrotink-llc.github.io/firmware/4k/changelog.html. An update adds or refines HDR CRT emulation presets, improves black frame insertion behaviour at 120 Hz, or adjusts the scanline mask resolution for specific output resolutions. The 4K supports profile saving, and a firmware update may change the profile format. Export your profiles to a second card before updating, then reimport them after verifying the new build.