Modify PX4 firmware

Can some one help me in toolchain installation for px4 firmware modification in controller. while installing i followed the official documentation, but some python related libraries could not be installed like jinja and few others. moreover, while giving command “sudo make px4_sitl jmavsim”, it stuck at ‘INFO [dataman] Unknown restart, data manager file ‘./dataman’ size is 11798680 bytes
INFO [simulator] Waiting for simulator to connect on TCP port 4560’. please tell me the reason and guide towards some solution to the problem. thank you.

Have you solved the problem?

The problem is solved but, since i was having other software issues like broken packeages and others. So, i reinstalled my ubuntu, started building from scratch and the problem did not arrive. Remember this issue is most probably related to java version. You have to make java 8 as default version instead of java 11.