I also discovered this page with suggestions on stopping the autoboot and entering commands:
Which gave me the following:
TIM-1.0
WTMI-armada-17.10.5-bb8f823
WTMI: system early-init
SVC REV: 5, CPU VDD voltage: 1.155V
Fill memory before self refresh...done
Fill memory before self refresh...done
Now in Self-refresh Mode
Restore termination values to original values
Exited self-refresh ...
Self refresh Pass.
DDR self test mode test done!!
Self refresh Pass.
DDR self test mode test done!!
QS GATING
=============
Calibration done: cycle = 0x00 tap =0x5F
CH0_PHY_RL_Control_CS0_B0[0xC0001180]: 0x0000005F
CH0_PHY_RL_Control_CS0_B1[0xC0001184]: 0x0000005F
QS GATING
=============
Calibration done: cycle = 0x00 tap =0x5D
CH0_PHY_RL_Control_CS1_B0[0xC00011A4]: 0x0000005D
CH0_PHY_RL_Control_CS1_B1[0xC00011A8]: 0x0000005D
DLL TUNING
==============
DLL 0xc0001050[21:16]: [0,2e,17]
DLL 0xc0001050[29:24]: [5,33,1c]
DLL 0xc0001054[21:16]: [0,2c,16]
DLL 0xc0001054[29:24]: [8,34,1e]
DLL 0xc0001074[21:16]: [0,3f,1f]
DLL 0xc0001074NOTICE: Booting Trusted Firmware
NOTICE: BL1: v1.3(release):armada-17.10.3:39a62a1
NOTICE: BL1: Built : 15:39:52, Jun 1 2NOTICE: BL2: v1.3(release):armada-17.10.3:39a62a1
NOTICE: BL2: Built : 15:39:54, Jun 1 2018NOTICE: BL31: v1.3(release):armada-17.10.3:39a62a1
NOTICE: BL31:
U-Boot 2017.03-armada-17.10.2-g14aeedc (Jun 01 2018 - 15:39:10 +0800)
Model: Marvell Armada 3720 Community Board ESPRESSOBin
CPU @ 1000 [MHz]
L2 @ 800 [MHz]
TClock @ 200 [MHz]
DDR @ 800 [MHz]
DRAM: 1 GiB
U-Boot DT blob at : 000000003f7161b8
Comphy-0: USB3 5 Gbps
Comphy-1: PEX0 2.5 Gbps
Comphy-2: SATA0 6 Gbps
SATA link 0 timeout.
AHCI 0001.0300 32 slots 1 ports 6 Gbps 0x1 impl SATA mode
flags: ncq led only pmp fbss pio slum part sxs
PCIE-0: Link down
MMC: sdhci@d0000: 0, sdhci@d8000: 1
SF: Detected mx25u3235f with page size 256 Bytes, erase size 64 KiB, total 4 MiB
Net: eth0: neta@30000 [PRIME]
Hit any key to stop autoboot: 0
Marvell>> setenv fdt_name 'boot/armada-3720-community.dtb'
Marvell>> setenv image_name 'boot/openwrt-armada-ESPRESSObin-Image'
Marvell>> setenv ethact 'neta0'
Marvell>> setenv set_bootargs 'setenv bootargs $console'
Marvell>> setenv bootmmc 'mmc dev 0; ext4load mmc 0:1 $kernel_addr $image_name;ext4load mmc 0:1 $fdt_addr $fdt_name;setenv bootargs $console root=/dev/mmcblk0p1 rw rootwait; booti $kernel_addr - $fdt_addr'
Marvell>> setenv bootcmd 'mmc dev 0; ext4load mmc 0:1 $kernel_addr $image_name;ext4load mmc 0:1 $fdt_addr $fdt_name;setenv bootargs $console root=/dev/mmcblk0p1 rw rootwait; booti $kernel_addr - $fdt_addr'
Marvell>> saveenv
Saving Environment to SPI Flash...
SF: Detected mx25u3235f with page size 256 Bytes, erase size 64 KiB, total 4 MiB
Erasing SPI flash...Writing to SPI flash...done
Marvell>> run bootmmc
switch to partitions #0, OK
mmc0 is current device
** File not found boot/openwrt-armada-ESPRESSObin-Image **
** File not found boot/armada-3720-community.dtb **
Bad Linux ARM64 Image magic!
Marvell>>
+++++++++++++++++++++++++++++++++++++++++
**************** UPDATE: I tried this again
+++++++++++++++++++++++++++++++++++++++++
OK, I reflashed the SD card and reset the EspressoBIN box and tried it again after forgetting the initial command:
ext4ls mmc 0:1
And I tried the process again:
Marvell>> TIM-1.0
WTMI-armada-17.10.5-bb8f823
WTMI: system early-init
(repeating data removed)
Hit any key to stop autoboot: 0
Marvell>> ext4ls mmc 0:1
<DIR> 4096 .
<DIR> 4096 ..
<DIR> 4096 lost+found
7391240 Image
7885 armada-3720-espressobin.dtb
328 boot.scr
Marvell>> setenv fdt_name 'boot/armada-3720-community.dtb'
Marvell>> setenv image_name 'boot/openwrt-armada-ESPRESSObin-Image'
Marvell>> setenv ethact 'neta0'
Marvell>> setenv set_bootargs 'setenv bootargs $console'
Marvell>> setenv bootmmc 'mmc dev 0; ext4load mmc 0:1 $kernel_addr $image_name;ext4load mmc 0:1 $fdt_addr $fdt_name;setenv bootargs $console root=/dev/mmcblk0p1 rw rootwait; booti $kernel_addr - $fdt_addr'
Marvell>> setenv bootcmd 'mmc dev 0; ext4load mmc 0:1 $kernel_addr $image_name;ext4load mmc 0:1 $fdt_addr $fdt_name;setenv bootargs $console root=/dev/mmcblk0p1 rw rootwait; booti $kernel_addr - $fdt_addr'
Marvell>> saveenv
Saving Environment to SPI Flash...
SF: Detected mx25u3235f with page size 256 Bytes, erase size 64 KiB, total 4 MiB
Erasing SPI flash...Writing to SPI flash...done
Marvell>> run bootmmc
switch to partitions #0, OK
mmc0 is current device
** File not found boot/openwrt-armada-ESPRESSObin-Image **
** File not found boot/armada-3720-community.dtb **
Bad Linux ARM64 Image magic!
Marvell>>