Blank screen after Armbian 20.04 install to emmc?

[psychoacoustic]

Hello,

I've been using Manjaro on my PBP, but coming from a Ubuntu background decided to give Armbian a try. I managed to first install Armbian Focal (directly from armbian.com) first on a USB thumbdrive, then from emmc, both successful - but then I decided try Armbian Hirsuite directly on emmc. I booted from the USB drive (Armbian Focal) and wrote the (unxz'd) image to /dev/mmcblk2 (only mmcblk device).

And now it doesn't boot. Here's the weird thing: I don't even see the usual Uboot messages flash by... did I manage to break it somehow? I thought writing to /dev/mmcblkX (no suffix) would write only to the "user" part.

The PBP doesn't change it's behaviour if I try booting off the USB thumbdrive. That drive is unchanged from the time I did the write to emmc, so it should be good in theory.

The power LED does indicate something is happening, luckily. From the (presumed) off state, pressing the power button a few seconds turns the LED on, first red, then shortly after green. If I tap the power button again a bit after, the LED goes off again after a short delay.

Any advice? If I can fix this without opening the case that'd be great, but I'm not too afraid to open it up either, and can wire myself a UART adapter if I have to (Waveshare CP2102 board, I just need to find a spare 3.5mm stereo jack in my parts bin). Or would even be pushing the reset button suffice?

Thank you for any hints!

[wdt]

Nearly always, an image will have a uboot package in the 1st 16M... so you likely have a new uboot
If you run fdisk on the uncompressed image, it will show 1st partition
starts at 32768 (sectors) or 62500 (manjaro)
The extra space for manjaro,, maybe they are thinking ahead, an ESP partition???
There is always an idbloader at 64 sectors, then a uboot.idb OR uboot.img and trust.img
(Uboot at 8M , if trust at 12M)
Try to see if it boots from sd? Otherwise, disable emmc, will NOT boot from usb with no working uboot
>Or would even be pushing the reset button suffice?
I think (not 100% sure) that a long pwr button press (20+ sec) equal reset button
This might help, clears out some residual configs that may be bad
Or, maybe not

[psychoacoustic]

Nearly always, an image will have a uboot package in the 1st 16M... so you likely have a new uboot
If you run fdisk on the uncompressed image, it will show 1st partition
starts at 32768 (sectors) or 62500 (manjaro)
The extra space for manjaro,, maybe they are thinking ahead, an ESP partition???
There is always an idbloader at 64 sectors, then a uboot.idb OR uboot.img and trust.img
(Uboot at 8M , if trust at 12M)
Try to see if it boots from sd? Otherwise, disable emmc, will NOT boot from usb with no working uboot
>Or would even be pushing the reset button suffice?
I think (not 100% sure) that a long pwr button press (20+ sec) equal reset button
This might help, clears out some residual configs that may be bad
Or, maybe not

Thank you, that worked! I wrote a fresh Manjaro (Sway) image onto a SD card, but it wouldn't just boot from it (20s pressing the power button did not help) - I did have to open up the PBP to flip the "disable booting from emmc"  switch. It then booted from SD, and can also boot from USB if the SD card is present.

Again, thanks! I'll be a bit more careful writing images to emmc from now on...

[TRS-80]

If you are still interested in Armbian, I recently got it working (via SD card and/or eMMC) here.