Updating bootloader on BPI-W2 flash

Does anyone know the Android ssh server default userid / password?

I have the Banana pi BPI-W2 with Android. I am trying to install Ubuntu on an SD card, using these instructions: BPI-W2 new image : How to make and run the 64-bit ubuntu 16.04 on SD card 2018-4-28 I was able to follow all the instructions in step 3, “Make a ubuntu root file system for W2 on a ubuntu PC.”, but after inserting the SD card and restarting the W2, it still boots to Android, so I assume I need to update the bootloader. I’m not sure how to update the bootloader via a cable in step 2, “Write the bootloader to the Banana Pi W2 flash”, so I am trying to connect using ssh on the local area network. Using putty on a windows pc, I am able to make the connection, but no combination of user ids (pi, banana, bananapi, raspberry, raspberrypi, root, admin) and passwords (blank, password, root, admin, pi, banana, bananapi, raspberry, raspberrypi) granted me access.

Any assistance with either a userid / password, or an explanation of how to directly connect the W2 to a Windows pc is greatly appreciated.

Update: I purchased a USB to UART cable. I successfully followed the instructions from Section 2, to reflash the bootloader, but now it just displays a green screen when the SD card is inserted before power on, and a black screen (i.e. the built-in Android O/S no longer boots up) when there is no SD card on power up. On the plus side, the bootloader now appears to be checking for the presence of an SD card, but something now fails to complete the boot process. I’m not even sure how to troubleshoot this.

Update: With the UART / USB cable connected to a Windows PC running a serial Putty session and the SD card inserted in the BPI-WP board, the putty client displays the boot up sequence and prompts for Ubuntu login, to which I successfully log in as root. The program, dmesg, continually reports the following:

[59262.435882] I/DC: [dc_wait_vsync_timeout 884] wait vsync timeout! vo_vsync_flag:0x00000101

Is this meaningful to anyone? I’ve searched for posts regarding vsync, but I’ve only found reports about issues with Xbox gaming.

It due to HDIM doesn’t work, we are working on it now.

I/DC: [dc_wait_vsync_timeout 884] wait vsync timeout! vo_vsync_flag:0x00000101

Also getting it, understand why. Any movement on using hdmi interface?

thanks much! G.

maybe, loss file. bluecore.audio or alsadaemon