Please re-flash everything with the same BSP version.
You cannot mix bootloder and rootfs with different BSP versions.
sudo ./tools/kernel_flash/l4t_initrd_flash.sh --external-device mmcblk1p1 \
-c tools/kernel_flash/flash_l4t_external.xml \
--showlogs --network usb0 jetson-agx-orin-devkit internal
Do this with 35.4.1; it will flash all of QSPI, where bootloader lives in, eMMC and SD card.
For setting boot orders in UEFI, there are a whole bunch of guide and discussion over the Internet, so please Google it yourself.