RUBIK PI3 Android 15 flashing issue: fastboot reboot fastboot stucks

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RUBIK PI3 Android 15 Flashing Issue

RUBIK PI3 Android 15 flashing issue: fastboot reboot fastboot stuck on recovery/menu, no volume buttons

I’m working on the RUBIK PI3 board with Android 15 source code and I’m blocked when trying to enter fastboot/fastbootd for flashing.

Environment

  • Board: RUBIK PI3
  • Host OS: Linux
  • I am generating Android images from source code, not using the prebuilt Rubik PI3 Android images directly
  • The source build completes successfully and the images are generated correctly
  • I am able to flash Android 15 to the RUBIK Pi 3 using the Qualcomm Device Loader (QDL) process https://www.thundercomm.com/rubik-pi-3/en/docs/rubik-pi-3-user-manual/1.0.0-a15/Flash-using-QDL
  • After flashing with QDL, the board boots normally into Android

Issue

When I run:

adb reboot bootloader
fastboot reboot fastboot

the board does not enter a usable fastboot session.

On the Linux workstation, fastboot shows:

< waiting for any device >

On the board display, I see a recovery/menu screen with text similar to:

Recovery mode
Press volume key to select, and press power key to select

However, since the board has no volume buttons, I cannot navigate the menu or select the fastboot mode.

Additional observations

  • adb devices works when Android is booted normally after the QDL flash
  • fastboot devices does not show the board
  • On Linux, lsusb shows the device as Qualcomm: 
    05c6:9500 Qualcomm, Inc.
  • This suggests the board may not be exposing a standard fastboot interface at this stage.

What I need help with

  1. How to enter fastboot/fastbootd on RUBIK PI3 when the board has no volume keys
  2. Whether the recovery menu can be controlled using the reset button or another method
  3. If 05c6:9500 indicates a Qualcomm emergency/download mode instead of fastboot
  4. The correct recovery or flashing procedure for this board when fastboot devices remains empty

Context

This issue is blocking our ability to flash and continue NFC development/testing on Android 15.

Any guidance or recommended recovery procedure would be greatly appreciated.

Thx and br