Do you have a serial console connected? If so, then you can manipulate the U-Boot environment and boot to a rescue SD card. Otherwise you will have to either clone then flash with a corrected clone, or simply flash fresh. For serial console see this (TX1 and TX2 are identical except for TX2 requiring software flow control…CTS/RTS does not function):
http://www.jetsonhacks.com/2017/03/24/serial-console-nvidia-jetson-tx2/
You could see if you can build a “rescue” SD card (I’ve found not all brands of SD card can be used as a root partition, YMMV even if this would otherwise work…name brands may actually matter). FYI, if there is no space then temp files cannot be written, and to some extent temp files are required for logins to succeed. This is a standard file system for a TX2, except that it runs from the SD card and you need to use serial console to reach it unless you’ve previously set up extlinux.conf to make this available.
In what follows the sample rootfs is unpacked on SD card, apply_binaries.sh is put on SD, and “extlinux.conf” is copied over.
<b>sudo -s</b>
lsblk
# Assumes /dev/sdg1; umount sdg1 if mounted. Assumes using "/mnt" as host PC mount point.
# The ^64bit,^metadata_csum are only required on some newer host systems.
mkfs.ext4 -O ^64bit,^metadata_csum /dev/sdg1
tar xvfj /home/dan/Documents/embedded/L4T/R27.1/src/Tegra_Linux_Sample-Root-Filesystem_R27.1.0_aarch64.tbz2
./apply_binaries.sh --root /mnt
# Now you have to add extlinux.conf:
mkdir /mnt/boot/extlinux
cp /where/ever/it/is/Linux_for_Tegra/bootloader/t186ref/p2771-000/extlinux.conf.sdcard /extlinux/extlinux.conf /mnt/boot/extlinux
sync
cd
umount /mnt
# Place the SD in the Jetson, boot with serial console, interrupt boot by pressing a key.
exit
Note of default boot environment:
help # Lists commands.
env print bootcmd # Lists sequences of variables expanded during boot.
# Note that this is the main boot command, and when you type "boot", this is what runs:
# env print distro_bootcmd
distro_bootcmd=for target in ${boot_targets}; do run bootcmd_${target}; done
# It is this which you want to edit (an edit will run this way once...if you don't save the environment edit it won't be permanent...this is good since you are only rescuing:
env print boot_targets
# Change to mmc1:
setenv boot_targets mmc1
# Verify:
env print boot_targets
boot
Now you can mount the eMMC on “/mnt”:
sudo -s
mount /dev/mmcblk0p1 /mnt
cd /mnt
# ...remove extra files, so on...when you have space to log in you can reboot and continue.
# Not all excess space needs to be cleared via SD card rescue...only enough to be able
# to generate temporary files.
shutdown -h now
# remove SD card.
# Boot.
If you don’t have a serial console and want to clone before flashing see this:
https://devtalk.nvidia.com/default/topic/1000105/jetson-tx2/tx2-cloning/
NOTE: You could use an SD card and mount to somewhere and put your software there to conserve space.