Zephyr buttonless DFU over uart when my application uses uart async for comms

Question

Using 54L15 DK for testing. Zephyr toolchain & SDK both v3.02. I have been through the DevAcadamy exercise which uses Blinky for its example, now I want to integrate into my own application. 
 My application uses the uart async adapter for both a CLI and data output. (Note the CLI is legacy code based around the uart callback, not using Zephyr's own CLI. The output is all done by printk). 
 How does the MCUMGR interact with the application's uart handling? 
 Secondly can you confirm that it's OK to enable both uart and BLE transports for DFU concurrently? 
 Thanks

Edvin · Accepted Answer

No. The bootloader and application doesn't run at the same point in time. This means that when the bootloader is done, before starting the application, it willl call nrf_cleanup_peripheral() (from v3.2.1\bootloader\mcuboot\boot\zephyr
rf_cleanup.c), which will disable and clean up the UART before starting the application, meaning that you can use the UART as you want to in your application. Just make sure that CONFIG_MCUBOOT_NRF_CLEANUP_PERIPHERAL=y is set. (This is set by default, unless it is specifically set to "n" in your application). 
 
 If you set 
 CONFIG_BOOT_SERIAL_WAIT_FOR_DFU=y and CONFIG_BOOT_SERIAL_WAIT_FOR_DFU_TIMEOUT=1000 
 Then it will wait for 1000ms after booting up in DFU mode, to see if it receives any DFU commands from mcumgr. If not, it will start the application. You can of course set the CONFIG_BOOT_SERIAL_WAIT_FOR_DFU_TIMEOUT higher than 1000ms. 
 
 Best regards, 
 Edvin

Zephyr buttonless DFU over uart when my application uses uart async for comms

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