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Carlinkit TBox UHD: HDMI Box, SM6225 vs SDM660, Firmware
Carlinkit TBox UHD hub: the SM6225 and SDM660 versions, HDMI out, the CarPlay/Android Auto pin switch, engineering codes, firmware and bug reports.
Specifications
- Chipset (SoC)
- SM6225 / SDM660
- Android
- 13
- RAM / storage
- 8 GB / 128 GB
- Variants
- SM6225 (HDMI), SDM660 (HDMI + extra USB port)
- How to tell it apart
- The Carlinkit box with an HDMI port (1080p output) and a pinhole switch for CarPlay / Android Auto. The SDM660 version also has a USB port; Settings → About shows which chip you have.
- Official pages
- SupportFirmware downloads
Identify your unit
The TBox UHD is the Carlinkit box with an HDMI port, so it can drive a rear-seat or second screen at up to 1080p. Carlinkit lists it with Android 13 and 8 GB RAM / 128 GB storage, in two hardware versions:
- SM6225: HDMI, USB-C to the car, microSD and SIM slots.
- SDM660: the same plus an extra USB port. This chip version shares firmware with the SDM660 TBox Ambient.
It also has a pinhole switch: press it with the ejector pin for 2 to 3 seconds to swap between CarPlay and Android Auto towards the car, without opening any menu. Carlinkit rates the UHD at 5 V 2 A, twice the input of the Plus and Ambient, which matters if your car’s port is weak (see accessories below).
Read the processor in Settings → About before you download firmware. The which TBox do I have page compares it with the Ambient and Ultra.
Engineering menu & codes
The UHD uses the same Carlinkit factory menu: Settings → Other → Factory settings, then a code.
- 4545: factory settings, including the start-up delay, the navigation bar switch and the temperature display.
- 166888: audio settings, including 44.1 kHz; save and wait for the reboot.
- 110144: clears the cache after an update.
If the protocol switch on the case does not do what you expect, switch the CarPlay / Android Auto protocol covers the menu route. The full code list is in the engineering codes table.
Firmware
Carlinkit’s download page (Support → Downloads on its own website) lists a combined Ambient and UHD file for SDM660 units. For any other build, the firmware request page explains how to ask support. This site does not host or link firmware files.
Updates go through the FOTA app and a FAT32 microSD card; see update TBox firmware with FOTA, and set the stock launcher first.
| Firmware date | Chip | Android | What changed, as reported |
|---|---|---|---|
| 13 Mar 2024 | SDM660 | 13 | First build the forum listed for the UHD and Ambient on SDM660 together. No change log. |
| 27 May 2024 | SM6225 | 13 | Official release shared with the Ambient: fixes for no 4G after a slow car connection, no sound on 4G calls and high CPU load after connecting with Bluetooth off. |
| 25 Jul 2024 | SM6225 | 13 | First SM6225 build the forum listed for the UHD alone. No change log. |
| 1 Apr 2025 | SDM660 | 13 | Listed on Carlinkit’s download page at the time of review. No change log. |
| 30 Dec 2025 | SM6225 | 13 | No change log. |
| 31 Jul 2026 | SM6225 | 13 | Newest SM6225 UHD build owners discussed. No change log. |
| 10 Aug 2026 | SDM660 | 13 | Newest SDM660 build owners discussed. No change log. |
The full list is on the firmware tracker.
Accessories that matter
- Y-cable or second power source. The UHD asks for up to 2 A. On a car port that supplies less, expect reboots and dropped connections; see AI box keeps rebooting.
- HDMI cable and screen. Output is 1080p at most; a 4K screen will not get a 4K picture.
- Cooling. Turn on the temperature display (4545 → Other) and read overheating shutdowns if the box gets hot.
- FAT32 microSD card of 32 GB or less, for updates.
How to report a bug
Collect:
- Chip (SM6225 or SDM660) and firmware date from Settings → About.
- Car make, model, year, head unit and protocol; whether HDMI is connected and to what.
- When the fault happens, and a short video.
Send it to [email protected]; the Carlinkit T-Box FAQ lists hours and channels. The general checklist is on how to report a bug.
Known issues and guides for this device
Generated from every article tagged with this device, most-confirmed first.
Power & connection
Car offers only Android Auto, or the box vanished after a mode change? Press the box's mode button 2–3 s or use the microSD file. Carlinkit TBox, Ottocast.
16 confirmed reports
Head unit ignores your AI box until you replug it? Set a start-up delay of 10–30 s so the box waits for the car. Carlinkit TBox, ApplePie UX999.
11 confirmed reports
Heat & throttling
Is your AI box too hot? Show its CPU temperature (4545 → Other) and act above about 80 °C, where throttling starts. Carlinkit TBox, Picasou 3 Pro.
4 confirmed reports
Audio & calls
Forcing 44.1 kHz (code 166888) helped some TBox Plus and Ultra 2 owners but caused crackle, silence or reboots for others. How to test it and undo it.
11 confirmed reports
Stutter, crackle or thin sound after moving your AI box from CarPlay to Android Auto? Factory reset the box. Carlinkit TBox Ambient, Plus, UHD and Ultra.
10 confirmed reports
Callers can't hear you through your AI box? Clear stale Bluetooth pairings, turn off assistant wake phrases, limit mic access. Carlinkit TBox, UX999.
8 confirmed reports
Firmware & recovery
Local firmware update for Carlinkit TBox Plus, Ambient, UHD and Ultra with the FOTA app and a FAT32 microSD card, step by step, plus fixes when it fails.
10 confirmed reports
TBox Ultra won't boot? Flash Carlinkit's official recovery package with QFIL in EDL mode: Flat build, SM6350 firehose, UFS. Plus fixes for Sahara errors.
8 confirmed reports
TBox Ambient or UHD sees the SIM only on first boot after a 2026 update? Set physical SIM in CloudSIM, disable the cloud SIM, or roll back to a 2025 build.
5 confirmed reports
QR code or Device not activated after a Carlinkit update? Get the box online with a SIM, then email the QR to Carlinkit support. TBox Plus, Ambient, Ultra.
4 confirmed reports
SIM, Wi-Fi & GPS
SIM shows signal but no mobile data on your AI box? Turn on data roaming, then enter the APN by hand. Carlinkit TBox Ambient, Plus, Ultra; Ottocast.
11 confirmed reports
Exclamation mark or 'no internet' on your AI box while apps still load? Turn off Android's captive-portal check over ADB. Carlinkit TBox Ultra, Ambient.
6 confirmed reports
Apps & launchers
CarCar Launcher asks for a licence again after a factory reset or reflash? Scan its QR code from the account that bought it. Licences stay with one device.
7 confirmed reports
AI box screen glares at night? Switch to a dark theme, lower the launcher's white point, and stop the theme flipping back to light. Carlinkit, Ottocast.
6 confirmed reports
Make the car's voice button open Gemini, Alexa or another assistant on your AI box: set it as Digital assistant app. Carlinkit TBox Ambient, Plus, Ultra.
5 confirmed reports
Hide the left navigation bar on Carlinkit (4545 → Other) or Ownice (1260 → Other), turn off the floating button in Display, or disable it over ADB.
2 confirmed reports
Carlinkit home-screen panes are widgets, not split screen. Make a real two-app split with code 121212 or the floating button. TBox Plus, Ambient, Ultra.
2 confirmed reports
Endless "Loading phone" after installing CarCar, Nova or another launcher? Turn off the system navigation bar (4545), set it as default. Carlinkit, Ownice.
2 confirmed reports
ADB, root & tinkering
Turn on ADB on a Carlinkit TBox (code 142618 or wireless debugging) or an Ottocast Picasou (port 65535 / 29528), connect, and switch it off again safely.
17 confirmed reports
No pinch-zoom on your TBox in Android Auto? Check your firmware, then add one build.prop line over ADB without root (Ultra, Plus) or patch the Ambient.
11 confirmed reports
Root a Carlinkit TBox Ultra or Ambient: back up boot_a/boot_b (init_boot on Ambient) with QFIL, patch in Magisk, write back, and how to undo it fully.
8 confirmed reports