Please review the attached document (Network Booting QNX on the Raspberry Pi 4 Model B.pdf), which contains the details on how to network boot QNX on a Raspberry Pi 4 Model B.
Below are the prerequisites needed to follow the attached document:
The host machine runs a modern version of Ubuntu (testing of this process was done on Ubuntu 22.04 and on a virtual machine of Ubuntu 20.04)
The host machine and your Pi are connected over the same network.
The network does not have any other DHCP servers that can interfere the network booting process.
You have a microSD card
Below is the summary of the steps involved in the tutorial:
IMPORTANT: This entry has been validated against the SDP version listed above. Use caution when considering this advice for any other SDP version. For supported releases, please reach out to QNX Technical Support if you have any questions/concerns.