Installing Ubuntu 20.04 (Focal) with BSP uBoot with deep sleep and sound

[TDC_PBP]

I just tried to write the image to the MicroSD card with DD using the exact same command you gave in your how-to post (except for changing the of in DD to match my MicroSD card) and then boot with the EMMC disabled...no luck. I got the same error:
U-Boot TPL 2020.01-ayufan-2013-gdb96b24f (Apr 13 2020 - 08:44:03)
Channel 0: LPDDR4, 50MHz
BW=32 Col=10 Bk=8 CS0 Row=15 CS1 Row=15 CS=2 Die BW=16 Size=2048MB
Channel 1: LPDDR4, 50MHz
BW=32 Col=10 Bk=8 CS0 Row=15 CS1 Row=15 CS=2 Die BW=16 Size=2048MB
256B stride
256B stride
lpddr4_set_rate: change freq to 400000000 mhz 0, 1
lpddr4_set_rate: change freq to 800000000 mhz 1, 0
Trying to boot from BOOTROM
Returning to boot ROM...

U-Boot SPL 2020.01-ayufan-2013-gdb96b24f (Apr 13 2020 - 08:44:03 +0000)
Trying to boot from MMC1
mmc_load_image_raw_sector: mmc block read error
Trying to boot from MMC1
mmc_load_image_raw_sector: mmc block read error
Trying to boot from MMC2
mmc_load_image_raw_sector: mmc block read error
SPL: failed to boot from all boot devices
### ERROR ### Please RESET the board ###

Then I re-enabled the EMMC (which has Ubuntu on it), and now I have the same error, except now the serial output is stopped on the line: Trying to boot from MMC2.

So the Ubuntu .img file boots just fine from MicroSD card when a different bootable OS is installed on the EMMC, but when there isn't (or the EMMC is disabled or the OS on the EMMC is Ubuntu), the image suddenly just doesn't boot??