Need Advice for Wiping eMMC on Dead LCD Pinebook Pro
#1
I was very impressed with my new Pinebook Pro for the entire day it ran after delivery, but the backlighting on the screen flickered and died, rendering my PBP unusable. (I can still barely see the Manjaro "M" logo on the splash screen during boot but, after that, I can't make out anything.

I have an RMA to return it for the Freemont CA service center, but I didn't encrypt my Manjaro installation so I'd like to to erase or re-flash the eMMC before returning it. I have some passwords saved in Firefox that I'd rather not ship off with the PBP. From what I recall about migrating Firefox passwords, they are stored in the clear, and with no whole drive encryption, my user password is insufficient protection.

Some may say I'm paranoid but there is an entire industry in India and the PRC that salvages disk drives from computer "recycling" bone yards to harvest personal data and passwords from them.

I have a Pinephone and dock but no Pinebook Pro dock. SSH connections are refused, because I never set it up on Manjaro.

Maybe forum members with greater knowledge of PBP than I can save me some time with suggestions or other ideas.

1. Boot via SD card to Jumpdrive. (Is there a Jumpdrive that runs on PBP?)
2. Image an OS with SSH enabled by default to an SD card and boot it. (Any suggested images?)
3. Try my Pinephone convergence dock for HDMI video out to my monitor. I know the dock is not designed for PBP, but perhaps the video out will work and I don't have a PBP USB-C video adapter.

I haven't looked into the serial port connection but it's probably a pretty big hassle to get setup.

Thanks!
-Cal
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#2
Update:

I have a postmarketOS SD card so I booted it. I can see the machine on my network and I can ping it but when I try to SSH to it:

Code:
ssh: connect to host 10.42.0.20 port 22: Connection refused

So SSH service is disabled in postmarketOS by default too.

If I can find an OS image, perhaps an older one before devs got all concerned about the security of SSH logons, I should be able to wipe my drive.

I also tried Pinetab Jumpdrive and it doesn't work on the Pinebook Pro. If I had JumpdriveI could wipe it with dd /dev/random or /dev/zero a few times.
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#3
(05-09-2021, 06:52 PM)calinb Wrote: Update:

I have a postmarketOS SD card so I booted it. I can see the machine on my network and I can ping it but when I try to SSH to it:

Code:
ssh: connect to host 10.42.0.20 port 22: Connection refused

So SSH service is disabled in postmarketOS by default too.

If I can find an OS image, perhaps an older one before devs got all concerned about the security of SSH logons, I should be able to wipe my drive.

I also tried Pinetab Jumpdrive and it doesn't work on the Pinebook Pro. If I had JumpdriveI could wipe it with dd /dev/random or /dev/zero a few times.
Do you have a USB-C to HDMI adapter?  You could plug in an external monitor and run, well, whatever.

Otherwise, Armbian has SSH open by default if I remember correctly.
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#4
(05-09-2021, 07:40 PM)carlosqueso Wrote: Do you have a USB-C to HDMI adapter?  You could plug in an external monitor and run, well, whatever.

Otherwise, Armbian has SSH open by default if I remember correctly.

Thanks very much for your help, carlosqueso!

I don't have a USB-C to HDMI adapter. All I have is my Pinephone convergence dock, which has that functionality but it is only claimed to work with the Pinephone. It might be a low risk, hardware-wise, to just try it.

Otherwise, I'll try Armbian, because I've been trying to hack system files to enable SSH on my pmOS SD card using another Linux system but no luck so far. I wonder if the Pinebook Pro pmOS is close enough to Pinephone that I could somehow chroot into it on my Pinephone to enable SSH. All I should need is a terminal in single user mode.
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#5
There is a problem with a uSD card you have never used,,
how will it know what ap (access point) and password?
Now if you have a usb->ethernet dongle
I have one, a "9700" (2nd half of usbid)....works fine,
but don't treat roughly, cable is flimsy (I have had to re-solder on dongle board)
OR
get a vt (control-alt-F3) (all this blindly, type carefully, on emmc, no SD card)
login as root
------------------
cd /sys/class/backlight/edp-backlight
echo 3200 > brightness
--------------------
(for some reason, space before and after ">" seems to be neccesary)
OR
try a mrfixit SD, usually reliable
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#6
(05-09-2021, 11:07 PM)wdt Wrote: There is a problem with a uSD card you have never used,,
how will it know what ap (access point) and password?
Now if you have a usb->ethernet dongle
I have one, a "9700" (2nd half of usbid)....works fine,
<snip>

Thanks, wdt!

Yes. Without a USB > Ethernet dongle, this is a problem.

From https://docs.armbian.com/

Quote:Ethernet adapter with DHCP and SSH server ready on default port (22)
Wireless adapter with DHCP ready (if present) but disabled. You can use armbian-config to connect to your router or create an access point

In theory, an SD-booted image could enable both SSH and USB networking. On my Pinephone, Mobian enables USB on a fresh boot, but SSH is disabled by default and the service must be started.

This entire task would be trivial on the Pinephone or a Pinetab, because Jumpdrive booted from SD could be used to mount the eMMC via USB on another system. I tried the Pinetab Jumpdrive on my Pinebook Pro and it doesn't boot. I guess I could try the Pinephone version too, but I doubt it will boot either.

Does vt (control-alt-F3) work on an SD card boot? Maybe I could use it blindly to enable SSH or maybe I could use it to enable SSH on my eMMC Manjaro.

Also from Armbian. [url=https://docs.armbian.com/User-Guide_Getting-Started/#how-to-connect-to-wireless][/url]

Quote:How to connect to wireless?
Required condition: a board with onboard or supported 3rd party wireless adapter on USB
If you know what is your wireless SSID:

nmtui-connect SSID
Maybe I could type the SSD for my open "guest" network blindly on vt.

I'm in with SSH! Tongue 

My Pinephone dock didn't work on my Pinebook Pro for HDMI video but it works for Ethernet!

I booted https://armbian.tnahosting.net/dl/pinebo...top.img.xz from an SD card (because years ago I used Ubuntu with XFCE and liked it and I'm an MX-Linux/XFCE fan now and thought I'd like to try Ubuntu Focal anyway.

I plugged the Ethernet cable into my router and found the PBP and its IP address on my router's web server "attached devices" page. Then I used SSH to connect to it as root (as described in the Armbian docs I linked earlier in this thread). Armbian had me setup locality and a non-root account, etc. so it will be ready to boot to the desktop after I get my PBP LCD screen repaired under warranty.

I think I'll archive my /home/<user> directory to the Armbian SD card and then delete it from the PBP's eMMC for the warranty work. Then I can easily restore it later.

If my Pinephone dock Ethernet had not worked, I would have tried to mount bootable SD cards on my other Linux machine and edit config and service management files to try to get SSH and some kind of networking (USB) running. Either that or some kind of chroot from my Pinephone into it or maybe dig into the Jumpdrive source and try to get it running on the PBP--all of which are probably large efforts.

Thanks carlosqueso and wdt! You gave me some good ideas. Armbian worked great and I would have tried an mrfixit SD image next.
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#7
Why not temporarily set up an unsecured access point just for this?

Do you have a serial console? That would be the simplest and most straightforward way to do this. Next simplest would he to pull the eMMC and wipe it oh another machine, with an adaptor.
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#8
(05-10-2021, 03:27 AM)KC9UDX Wrote: Why not temporarily set up an unsecured access point just for this?

I have "guest" APs in the clear but no OS that I've found will initially connect to them (upon first boot) without selecting the AP's SSD.

(05-10-2021, 03:27 AM)KC9UD Wrote: Do you have a serial console?  That would be the simplest and most straightforward way to do this.  Next simplest would he to pull the eMMC and wipe it oh another machine, with an adaptor.
No--no serial console and no other machine to wipe the eMMC, unless it is compatible with my Pinephone.

I was lucky that my Pinephone dock worked as a Pinebook Pro USB to Ethernet dongle, even though the HDMI didn't work. Using my Pinephone dock and Armbian (which has both DHCP client and server and SSH enabled on Ethernet for first boot), it was actually a very easy task. The tough part was discovering that these two tools were up for it! Armbian is designed to support headless SBC so it makes sense it would work. Most other OS devs are irrationally paranoid to enable SSH on first boot (security keys CAN come later or the service CAN be disabled later, after all).
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#9
Since you have ssh, check brightness as middle OR above,,
maybe you won't have to send away
At one point (8 months ago?) manjaro had that problem,, tiny backlight value
It was from a change in the number range, IIRR
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#10
(05-10-2021, 12:30 PM)wdt Wrote: Since you have ssh, check brightness as middle OR above,,
maybe you won't have to send away
At one point (8 months ago?) manjaro had that problem,, tiny backlight value
It was from a change in the number range, IIRR

Good idea but, because of the way the backlight flickered a few times when I moved the display back and forth and then went completely dark, I think it's a hardware problem. However, no harm in trying. On Armbian:

Code:
@pinebook-pro:~$ cd /sys/class/backlight/edp-backlight
@pinebook-pro:/sys/class/backlight/edp-backlight$ echo 3200 > brightness
-bash: brightness: Permission denied
@pinebook-pro:/sys/class/backlight/edp-backlight$ sudo echo 3200 > brightness
-bash: brightness: Permission denied
@pinebook-pro:/sys/class/backlight/edp-backlight$ sudo su
root@pinebook-pro:/sys/devices/platform/edp-backlight/backlight/edp-backlight# sudo echo 3200 > brightness
root@pinebook-pro:/sys/devices/platform/edp-backlight/backlight/edp-backlight#

Only sudo su... worked but the screen is still black. Cry

Again, thanks so much for the tips. It might have taken me a long time to find an OS like Armbian and I was also lucky that my PinePhone dock was a usable Ethernet dongle!
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