2.2 KiB
Notes on Hello Perso sample app.
Hello Perso is a sample app from the LedgerHQ repository blue-sample-apps. It's stated purpose is to be a "a simple application showing the UI and master seed derivation."
Compiling:
Compiles fine inside Docker image, as in the process described in the Getting Started tutorial (which takes you through the Hello World tutorial).
In extracting the hex-encoded compiled app from the docker container to my local machine, I changed the app name as follows:
sudo docker cp [container_id]:/home/blue-sample-apps/blue-app-helloperso/bin/app.hex perso-app.hex
I then loaded the app onto the Nano S using the following, and then discovered a problem:
python -m ledgerblue.loadApp --targetId 0x31100002 --apdu --fileName perso-app.hex --appName HelloPerso --appFlags 0x00 --icon ""
The problem: Hello Perso app requires the APPLICATION_FLAG_GLOBAL_PIN
permission flag. I had just copied and pasted my loadApp command line for
HelloWorld and changed the app name and image name. But the --appFlags
argument needed to be changed to --appFlags 0x40.
Symptoms: With the wrong permissions set, even though the app was successfuly loaded onto the device, it would freeze the Nano every time I started the app, requiring a power-cycle to get back to the dashboard.
The correct load command was:
python -m ledgerblue.loadApp --targetId 0x31100002 --apdu --fileName perso-app.hex --appName HelloPerso --appFlags 0x40 --icon ""
How to remove apps:
Problem Two: Repeating the loadApp() command with the correct flags failed because the app already existed on the device. It apparently won't overwrite. Thus I had to find a delete command, which fortunately is referenced in the Makefile. To manually delete the app, this is the command:
python -m ledgerblue.deleteApp --targetId 0x31100002 --appName HelloPerso
Permission flags defined:
The 0x40 permission flag that was needed is defined by macro constant
APPLICATION_FLAG_GLOBAL_PIN in
nanos-secure-sdk/include/os.h,
along with many other application flags.