No HDMI display - locks up at "starting kernel" when looking through serial console

So, I’m exceedingly new to Linux, and am working on the TK1 as part of a project. My goal was to enable SPI on the board, and I followed this guide for the most part, instead opting to follow the uboot link for that part alone:

After copying the zImage, I rebooted the board, at which point nothing showed up on the monitor it had been working on for the past week. After checking to see if the USB and uUSB ports were still working, I concluded that it is the HDMI output of the board that is failing (board powers on, fan is on, uUSB connects to the virtual machine I’m running when in recovery mode, mouse still receives power). Due to my limited supplies, I don’t have a wide variety of monitors or cables to check with, though I did check with a different brand of monitor and a different HDMI cable and there was still no output. As a last-ditch effort, I setup the serial console, and found these results on turning on the board (results are typed, am completely :

Board: NVIDIA Jetson TK1
I2C: ready
MMC: Tegra SD/MMC: 0, Tegra SD/MMC: 1
*** Warning - bad CRC, using default environment

tegra-pcie: PCI regions:
tegra-pcie: I/O: 0x12000000-0x12010000
tegra-pcie: non-prefetchable memory: 0x13000000-0x20000000
tegra-pcie: prefetchable memory: 0x20000000-0x40000000
tegra-pcie: 2x1, 1x1 configuration
���Ʌ�pcie: probing port 0, using 2 lanes
tegra-pcie: link 0 down, retrying
tegra-pcie: link 0 down, retrying
tegra-pcie: link 0 down, retrying
tegra-pcie: link 0 down, ignoring
tegra-pcie: probing port 1, using 1 lanes
In: serial
Out: serial
Err: serial
Net: RTL8169#0
Warning: RTL8169#0 using MAC address from net device

Hit any key to stop autoboot: 0
MMC: no card present
switch to partitions #0, OK
mmc0(part 0) is current device
Scanning mmc 0…
Found /boot/extlinux/extlinux.conf
Retrieving file: /boot/extlinux/extlinux.conf
813 bytes read in 142 ms (4.9 KiB/s)
Jetson-TK1 eMMC boot options
1: primary kernel
Enter choice: 1: primary kernel
Retrieving file: /boot/zImage
5665824 bytes read in 190 ms (28.4 MiB/s)
append: console=ttyS0,115200n8 console=tty1 no_console_suspend=1 lp0_vec=2064@0t
Retrieving file: /boot/tegra124-jetson_tk1-pm375-000-c00-00.dtb
59637 bytes read in 281 ms (207 KiB/s)
Kernel image @ 0x81000000 [ 0x000000 - 0x567420 ]

Flattened Device Tree blob at 82000000

Booting using the fdt blob at 0x82000000
Using Device Tree in place at 82000000, end 820118f4
get_board_serial: I2C read of bus 1 chip 86 addr 4 failed!

Starting kernel …

And from there it never changes. How do I fix this?

It looks like the kernel was either never loaded, or it was loaded with a kernel not configured for serial console (or perhaps a kernel which was not configured sufficiently to even attempt to run serial console). Since it looks like extlinux.conf itself and the firmware files loaded, the problem is not one of being unable to read the partition with the zImage. I see no message about the image not being found. Odds tend towards kernel configuration issues.

So I have not studied the SPI article in any depth, but some of the reference is for the R19.x L4T series, while your root file system may be from R21.x if you have ever flashed it (and R21.4 is highly recommended). Can you give more information about which L4T version was on the Jetson before updating the kernel, and how the kernel was configured?