Flashing a coral dev board per the getting started guide results in the the error Wrong image format for "source" command. This error is what is displayed in the serial console when the SD card is inserted in the board and the board is powered up - full output below. I didn't find any documentation for this problem so I am posting it here in case anyone else has this issue.
U-Boot SPL 2019.04.1 (Apr 29 2020 - 18:40:05 +0000)
power_bd71837_init
Board id: 2
DDRINFO: start DRAM init
DDRINFO:ddrphy calibration done
DDRINFO: ddrmix config done
Normal Boot
Trying to boot from MMC2
hdr read sector 300, count=1
U-Boot 2019.04.1 (Apr 29 2020 - 18:40:05 +0000), Build: jenkins-enterprise.uboot-imx-1
CPU: Freescale i.MX8MQ rev2.0 1500 MHz (running at 1000 MHz)
CPU: Commercial temperature grade (0C to 95C) at 33C
Reset cause: POR
Model: Freescale i.MX8MQ Phanbell
DRAM: 1 GiB
MMC: FSL_SDHC: 0, FSL_SDHC: 1
Loading Environment from MMC... *** Warning - bad CRC, using default environment
In: serial
Out: serial
Err: serial
BuildInfo:
- ATF
- U-Boot 2019.04.1
flash target is MMC:0
Net:
Error: ethernet@30be0000 address not set.
Error: ethernet@30be0000 address not set.
eth-1: ethernet@30be0000
Fastboot: Normal
Normal Boot
Hit any key to stop autoboot: 0
** No partition table - mmc 1 **
## Executing script at 40480000
Wrong image format for "source" command
## Starting auxiliary core at 0x00000000 ...
u-boot=>
This error results from a bad SD card, or perhaps one that has already been used (formatted) for other uses. I was able to bypass this error and successfully install the OS by burning the image per the the getting started guide on a brand new SD card (I used a Samsung 128GB Pro Endurance card). I used balenaEtcher on a mac, which burns the image in just a few minutes.