GS6/GS6 Pro: fastboot flashing unlock returns OKAY but bootloader stays locked

Using /e/OS Setup
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Device: Gigaset GS6 (GS6_Venus), , brand new/unopened before this attempt, stock Android (model string E940-3043-00 in normal USB mode).

e/OS build: IMG-e-4.1.1-a16-20260717651034-official-GS6_Venus.zip (SHA256 verified match).

Setup: Arch Linux, android-tools (pacman), fastboot/adb reach the device fine in both normal and bootloader mode.

Steps taken:

  1. USB debugging + OEM unlocking both enabled and confirmed ON in Developer options.

  2. adb reboot bootloader → device enumerates correctly (fastboot devices shows serial as fastboot).

  3. fastboot flashing unlock → returns OKAY [5.09s] every time. Screen briefly shows fast-scrolling small text then returns to a static >>FACTORY mode screen. No visible confirmation prompt to accept with Volume Up (tried holding/pressing repeatedly, no effect).

  4. fastboot flashing unlock_critical → same OKAY/behavior.

  5. fastboot flashing get_unlock_ability → returns unlock_ability is true.

  6. Ran flash_GS6_Venus_factory.sh → aborts with: “Your device’s bootloader is still locked. Please follow the instructions to unlock the bootloader! / Device does not support ‘oem device-info’, skipping critical unlock check. / Your phone is not ready for flashing yet.”

  7. Confirmed via adb shell getprop ro.boot.flash.locked → 1, and ro.boot.verifiedbootstate → green. Bootloader genuinely still locked after every unlock attempt, despite unlock_ability being true and every command returning OKAY.

Question: Does GS6/GS6 Pro need a different unlock procedure than standard fastboot flashing unlock (e.g. a visible confirmation step I’m missing, a different button combo, or a Gigaset-specific requirement not in the doc.e.foundation install page)? No matching issue found in GitLab (GS6_Venus shows 0 known issues).

**Edit:** A few more data points:

- Chip is MT6878 (Dimensity 7300), confirmed via `MT6878_Android_scatter.xml` in the flash package.

- Tried the vendor-bundled fastboot binary from the e/OS zip itself (`bin-linux-x86/fastboot`) instead of the distro-packaged one — identical behavior (OKAY, but `ro.boot.flash.locked` stays `1`). Rules out the tool/binary as the cause.

- `fastboot flashing get_unlock_ability` returns `unlock_ability is true`.

- Found a similar-looking issue on another MediaTek Dimensity chip (MT6833) via mtkclient’s GitHub: unlock command reports success but the bootloader doesn’t actually end up unlocked afterward (github.com/bkerler/mtkclient/issues/764). Same chip family (MT6878) is mentioned working with mtkclient’s exploit on other devices (e.g. Redmi Note 14 Pro 5G).

Has anyone tried mtkclient/BROM mode specifically on the GS6/GS6 Pro? If so, which BROM entry combo works on this device? Would rather not attempt this blind on a device with no documented BROM procedure.

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No need to post your serial number, you should remove it from post.

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System installed platform tools are advised against here

Edit.

mentioned on the install page with

Tip: In case of issues with the latest fastboot version, try using version 35.0.2-android-tools

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I just went through this process on a new Gigaset GS6 Pro. There’s a step you are missing - when you send the command “fastboot flashing unlock” you have to quickly push the volume down button on the screen. You only have 3 seconds to read the message on the GS6 Pro and to correctly respond. I had to go through this several times to work it out.

Also, I found the phone would stop responding to fastboot commands. Eventually I realised that if I disconnect the USB cable between each fastboot command it would work. I also built the android tools version 35.02 but it made no difference.

So in a nutshell - in your comment it looks like you are not reading and responding to the text that appears on the GS6 Pro screen (depending on versions etc..)

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