Well, it's ten days since my last email to Planet. No reply this time. Perhaps worse, I have discovered another issue with my Astro, which seems to make fixing my dead screen even harder.
Using the developer options, I set the default USB configuration to file transfer, so the Astro would immediately show up as a portable device in Windows as soon as I plug the USB cable in. I then rebooted without HDMI, logged in blindly and connected a USB cable from the left side port to a Windows computer. The Astro begun charging, but there was no USB connection sound and the Astro did neither show up in the file manager, nor in the device manager.
I tried another cable, another port, another computer. My Cosmo gladly shows up using any cable in any port on either computer. The Astro does not. I took a screenshot, just in case the Astro was showing an error on its disabled screen, but after rebooting with HDMI, the screenshot just showed my Android home screen. Being able to take a screenshot at least proved that the Astro was indeed fully booted and logged in, so it should really have showed up in Windows.
I installed ADB on my computer, rebooted the Astro blindly, and plugged in the USB cable again. Windows didn't detect it this time either and, as I suspected, ADB could not see any devices. After some tinkering I got ADB to work over WiFi, which is nice, since I can then use it while the HDMI is attached. I am able to start a shell via ADB over WiFi, but I'm not sure what I could use it for in this context. I am also able to reboot the Astro to fastboot mode. With HDMI attached I can see fastbootd start, but since fastbootd can't use WiFi, I have no way to see or set the active boot slot.
I could try the 07B update anyway and just hope for the best, but that would reasonably overwrite the boot slot with the factory image, meaning I would no longer have even a theoretical ability to return to a known good firmware image. That might be undesirable.
Ideas anyone? Having a non-mobile mobile is starting to get tedious.
Edit: Btw. I was also able to get screencasting from my Astro to computer working, but to see what I was doing on the Astro, I naturally had to also have HDMI attached, so I didn't gain much. Would I be able to somehow start the screencasting after a blind login, it might be useful, but there seems to be too many steps involved to be able to do that blindly, and as long as basic USB cable connectivity doesn't work, I'm kind of stuck anyway.