Can you try with AGX devkit carrier board? Reflash it with our SW to see if can work.
You can go to ~/nvidia on your host machine and find out the Linux_for_Tegra for t194, and then run command
sudo ./flash.sh jetson-agx-xavier-industrial mmcblk0p1
Please remember to put the device into recovery mode before running the command.
Share me the log if error happens.
Or you may refer to below topic if it’s similar issue: Jetson AGX Xavier Industrial Boot Up Issue - #20 by emrerrdhx