Thank you for your support.
Below is the message of “sudo gdisk /dev/sdb.”
It does show reading error.
However, this SDcard was flashed by Sdkmanager 0.9.14 on Nano.
nvn2@nvn2-desktop:~$ sudo gdisk /dev/sdb
[sudo] password for nvn2:
GPT fdisk (gdisk) version 1.0.3
Problem opening /dev/sdb for reading! Error is 2.
The specified file does not exist!
Once the error occurred, please put this sdcard to your x86 host and run gdisk command.
Also, please read the error you pasted in #3.
Your error indicates sdb does not exist, so please confirm if your sdcard is sdb or not. If not, please use the right name and run gdisk command again.
Problem opening /dev/sdb for reading! Error is 2.
The specified file does not exist!
As the test results we got, the same SDcard has different behavior on a new Nano device or a used Nano device.
Here are the steps we did.
Sdcard flashed on Nano with sdkmanager.
Boot normally — GPT not present.
Unplug the sdcard and put the sdcard to a new nano device → cannot boot
Use a x86 system to check gdisk on sdcard again → GPT: present
However, if the step 3 replaced a used Nano:
3. Unplug the sdcard and put the sdcard to a used nano device → boot successfully.
4. Use gdisk on sdcard again → GPT not present. (see attached.)
On a x86 system:
sudo gdisk /dev/sdb
GPT fdisk (gdisk) version 1.0.1
Partition table scan:
MBR: protective
BSD: not present
APM: not present
GPT: present
Found valid GPT with protective MBR; using GPT.
Command (? for help): v
No problems found. 1748497 free sectors (853.8 MiB) available in 1
segments, the largest of which is 1748497 (853.8 MiB) in size.
The issue can only be duplicated with new Nano devices which are new purchased.
Unfortunately, we tested 4~6 sdcards and all got the same error result.
Thank you for your feedback, we have logged an internal bug to track this fix. It is targeted for 1H 2020.
Before that, please be sure to flash the device with the SDKM, then boot first.