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AI Box Fix

Firmware & recoveryReviewed

TBox Ambient Loses the SIM After 2026 Firmware

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.

Quick answer

Flash Carlinkit's official recovery files for your model, set the CloudSIM app to physical SIM only, then reinstall the 2026 build: that made the SIM work on two QCM6225 units. If you would rather not use QFIL, disabling the cloud-SIM app (one report) or rolling back to a 2025 build with Local update (one report) also brought the SIM back.

Symptoms

  • After a 2026 update the box finds the SIM only on the first boot; every later boot says there is no SIM
  • Entering 4545 in Factory settings and rebooting brings the SIM back until the next restart
  • The network name shows a cloud-SIM provider such as GlocalMe instead of your carrier, and data stops
  • The SIM works in a phone and worked in the same box on a 2025 build
  • A CloudSIM app appeared in the app list after the update

Applies to

Connection to the car
CarPlay and Android Auto
Firmware in confirmed reports
Carlinkit TBox Ambient: 2026-04-01; Carlinkit TBox UHD: 2026-04-01; Carlinkit TBox Ambient: 2026-09-03; Carlinkit TBox Ambient: 2025
Highest risk on this page
Brick risk
Status
Workaround confirmed by the community

Why it happens

Carlinkit’s 2026 builds for the TBox Ambient on QCM6225 (and the UHD on the same chip) bring a cloud-SIM service: a built-in eSIM, managed by an app called CloudSIM and linked to the GlocalMe service. When the box chooses the cloud SIM over the physical slot, your own SIM is greyed out, missing after the first boot, or replaced by the cloud-SIM operator name with no data.

Owners first noticed it on builds after 11 Nov 2025. One Ambient owner saw the SIM only on the first boot of every build after that, and found that opening 4545 and rebooting brought it back until the next restart. Experienced owners found that the SIM came back once physical SIM was given priority in CloudSIM on a clean install, which points at the SIM-selection setting rather than the modem itself.

So the fixes either set that priority from a clean state, switch the cloud SIM off, or go back to firmware without it. General SIM problems that started without an update are covered in AI box SIM card not working.

Fixes, ranked

Recover with official files, choose physical SIM, then reinstall the 2026 build

  • Brick risk
  • Time: 1–2 hours
  • Worked for 2 of 2 reports

Warranty warning: this changes system partitions. A wrong file or an interrupted step can leave the box unbootable, and manufacturers treat it as outside warranty. Back up first and keep the undo steps open.

  1. Ask Carlinkit support ([email protected]) for the official recovery files for your exact model and chip. Owners used the 20 May 2025 Ambient set.
  2. Flash them with QFIL from a Windows PC, following the instructions that come with the files and the QFIL recovery guide. This erases the box.
  3. Boot the box, open the CloudSIM app from the app list, go to its Settings and choose physical SIM only (called physical SIM priority on some versions). Restart.
  4. Check that your SIM shows your carrier and has data.
  5. Install the 2026 build you want with FOTA Update → Local update, as in the local update guide.
  6. Check the SIM again after two restarts.

An experienced owner first met this on a friend’s TBox UHD 6225: after installing the 1 Apr 2026 build the SIM was unavailable, and it worked only once the recovery files and the physical-SIM setting went in before 1 Apr. On their own Ambient the SIM was likewise not detected on 1 Apr until doing exactly this, and afterwards they called 1 Apr the best build that box had run. They planned the same route for the 15 Jan 2026 build on a UHD 6225 but did not post the result.

The firmware channel’s note on the recovery set adds one caution: the set contains more than one partition-layout file, and picking the wrong one leaves the SIM dead, so use the one the instructions name.

Disable the cloud-SIM app if your build has no CloudSIM settings

  • Safe
  • Time: 5 minutes
  • Worked for 1 of 1 report
  1. Open Settings → Apps and show system apps (menu at the top right).
  2. Look for the cloud-SIM service: CloudSIM, GlocalMe or a similar name.
  3. Open it and tap Disable. Confirm.
  4. Restart the box and check mobile data with Wi-Fi off.

An Ambient owner on the 3 Sep 2026 build found no CloudSIM app to change the setting, disabled the cloud-SIM app instead and reported that everything worked. To undo, open the same app in Settings → Apps and tap Enable.

Roll back to an official 2025 build

  • Advanced
  • Time: 30 minutes
  • Worked for 1 of 1 report

Warranty warning: this uses developer or engineering access. Follow the undo steps afterwards; some sellers refuse warranty claims on units with debugging left enabled.

  1. Get the last official 2025 firmware for your exact model from Carlinkit support.
  2. Set the stock launcher as the default home app; see stock launcher before a firmware update.
  3. Copy the file unchanged to the root of a FAT32 microSD card and install it with FOTA Update → Local update.
  4. Restart twice and check the SIM each time.
  5. If the SIM is still missing, clear the cache (110144) and then factory reset.

The owner who first reported SIM-only-on-first-boot rolled back to a 2025 build, and the SIM worked straight away. On that box, builds up to 11 Nov 2025 had been fine.

Use a third-party build that has no cloud SIM

  • Advanced
  • Time: 1 hour
  • Worked for 1 of 1 report

Warranty warning: this uses developer or engineering access. Follow the undo steps afterwards; some sellers refuse warranty claims on units with debugging left enabled.

  1. Read third-party firmware for Carlinkit first: what changes, what breaks and how to return.
  2. Install the third-party build following its publisher’s own instructions.
  3. Check the SIM after two restarts.

The same Ambient owner later moved from the 2025 rollback to the current Bruxe build, a third-party firmware without the cloud-SIM service, and the SIM worked there too. Carlinkit does not support third-party firmware, and owners disagree on whether a full reset is needed when switching.

Things to try (unverified)

  • Switch CloudSIM to physical SIM without reflashing. If your build has the CloudSIM app, open it → Settings → physical SIM only, and restart. Owners recommended this; one found the setting and thanked the helpers, but did not say whether data came back. It costs nothing to try before the routes above.
  • APN and SIM PIN. If the SIM shows your carrier but has no data, the cause may be ordinary: Carlinkit’s SIM guide says to add the APN under Settings → Network & internet → Mobile network → Access Point Names and to remove the SIM PIN in a phone.

If nothing works

Record the model and chip from Settings → About (QCM6225 or SDM660 on the Ambient), the firmware date, the carrier, whether the SIM shows as missing, grey, or present without data, and what the CloudSIM app shows. A screenshot of Settings → About → SIM status helps.

Send that to Carlinkit support at [email protected] and ask which official build keeps the physical SIM working on your unit. If your carrier blocks the box’s IMEI or your plan does not allow data in a modem, a data-only SIM is the cleaner answer. If none of the routes brings the SIM back, a warranty claim is reasonable; start here compares the box families if you are replacing it.

Parts the fixes above need

  • Data-only / IoT SIM card

    AI boxes use the SIM as a modem; a data-only plan avoids voice-plan device locks.

Related fixes

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Changelog

  • Last reviewed against new community reports:
  • Confirmed by 5 community reports on Carlinkit TBox Ambient, Carlinkit TBox UHD.
  • Page updated:

"Confirmed" means a community member reported that the fix worked on their unit. We have not tested it on our own hardware. How we verify.