I managed to flash the newer u-boot/l-boot using USB_BOOT button and now I can see the u-boot prompt but the script failed to flash the linaro stretch to internal mmc.
This error repeats over and over. No worries tho as long as u-boot is there I can use extlinux.conf to load an OS
poplar# usb reset
resetting USB...
USB0: USB EHCI 1.00
scanning bus 0 for devices... 3 USB Device(s) found
scanning usb for storage devices... 1 Storage Device(s) found
scanning usb for ethernet devices... 0 Ethernet Device(s) found
poplar# fatload usb 0:1 ${scriptaddr} install.scr
reading install.scr
1841 bytes read in 21 ms (85 KiB/s)
poplar# source ${scriptaddr}
## Executing script at 32000000
reading mbr.gz
159 bytes read in 16 ms (8.8 KiB/s)
Uncompressed size: 512 = 0x200
MMC write: dev # 0, block # 0, count 1 ... 1 blocks written: OK
reading partition1.1-of-1.gz
223849 bytes read in 33 ms (6.5 MiB/s)
Uncompressed size: 4193792 = 0x3FFE00
MMC write: dev # 0, block # 1, count 8191 ... 8191 blocks written: OK
reading partition2.1-of-1.gz
7229954 bytes read in 229 ms (30.1 MiB/s)
Uncompressed size: 134217728 = 0x8000000
MMC write: dev # 0, block # 8192, count 262144 ... 262144 blocks written: OK
reading partition3.1-of-8.gz
52855584 bytes read in 1530 ms (32.9 MiB/s)
Uncompressed size: 268435456 = 0x10000000
MMC write: dev # 0, block # 270336, count 524288 ... 524288 blocks written: OK
reading partition3.2-of-8.gz
EHCI timed out on TD - token=0x2c008d80
EHCI timed out on TD - token=0x80008d80
EHCI timed out on TD - token=0x80008d80
EHCI timed out on TD - token=0x80008d80
EHCI timed out on TD - token=0x80128d80
EHCI timed out on TD - token=0x80008d80
EHCI timed out on TD - token=0x80008d80
EHCI timed out on TD - token=0x80008d80
EHCI timed out on TD - token=0x801f8c80
EHCI timed out on TD - token=0x80008d80
EHCI timed out on TD - token=0x80008d80
EHCI timed out on TD - token=0x80008d80
EHCI timed out on TD - token=0x801f8c80
EHCI timed out on TD - token=0x80008d80
EHCI timed out on TD - token=0x80008d80
EHCI timed out on TD - token=0x80008d80
EHCI timed out on TD - token=0x801f8c80
EHCI timed out on TD - token=0x80008d80
EHCI timed out on TD - token=0x80008d80
EHCI timed out on TD - token=0x80008d80
EHCI timed out on TD - token=0x801f8c80
EHCI timed out on TD - token=0x80008d80
EHCI timed out on TD - token=0x80008d80
EHCI timed out on TD - token=0x80008d80
Error reading cluster
** Unable to read file partition3.2-of-8.gz **
Error: inflate() returned -3
poplar# reset
resetting ...
INFO: PSCI Power Domain Map:
INFO: Domain Node : Level 1, parent_node -1, State ON (0x0)
INFO: Domain Node : Level 0, parent_node 0, State ON (0x0)
INFO: Domain Node : Level 0, parent_node 0, State ON (0x0)
INFO: Domain Node : Level 0, parent_node 0, State ON (0x0)
INFO: CPU Node : MPID 0x0, parent_node 0, State ON (0x0)
INFO: CPU Node : MPID 0xffffffffffffffff, parent_node 0, State OFF (0x2)
INFO: CPU Node : MPID 0xffffffffffffffff, parent_node 0, State OFF (0x2)
INFO: CPU Node : MPID 0xffffffffffffffff, parent_node 0, ▒
Bootrom start
Boot Media: eMMC
Decrypt auxiliary code ...OK
lsadc voltage min: 000000FF, max: 000000FF, aver: 000000FF, index: 00000000
Entry boot auxiliary code
Auxiliary code - v1.00
DDR code - V1.1.2 20160205
Build: Mar 24 2016 - 17:09:44
Reg Version: v134
Reg Time: 2016/03/18 09:44:55
Reg Name: hi3798cv2dmb_hi3798cv200_ddr3_2gbyte_8bitx4_4layers.reg
Boot auxiliary code success
Bootrom success
LOADER: Switched to aarch64 mode
LOADER: Entering ARM TRUSTED FIRMWARE
LOADER: CPU0 executes at 0x000ce000
INFO: BL1: 0xe1000 - 0xe7000 [size = 24576]
NOTICE: Booting Trusted Firmware
NOTICE: BL1: v1.3(debug):e5a3825
NOTICE: BL1: Built : 13:47:53, May 16 2017
INFO: BL1: RAM 0xe1000 - 0xe7000
INFO: BL1: Loading BL2
INFO: Loading image id=1 at address 0xe9000
INFO: Image id=1 loaded at address 0xe9000, size = 0x5008
NOTICE: BL1: Booting BL2
INFO: Entry point address = 0xe9000
INFO: SPSR = 0x3c5
NOTICE: BL2: v1.3(debug):e5a3825
NOTICE: BL2: Built : 13:47:56, May 16 2017
INFO: BL2: Loading BL31
INFO: Loading image id=3 at address 0x129000
INFO: Image id=3 loaded at address 0x129000, size = 0x7020
INFO: BL2: Loading BL33
INFO: Loading image id=5 at address 0x37000000
INFO: Image id=5 loaded at address 0x37000000, size = 0x566b7
NOTICE: BL1: Booting BL31
INFO: Entry point address = 0x129000
INFO: SPSR = 0x3cd
INFO: Boot bl33 from 0x37000000 for 353975 Bytes
NOTICE: BL31: v1.3(debug):e5a3825
NOTICE: BL31: Built : 13:48:00, May 16 2017
INFO: ARM GICv2 driver initialized
INFO: BL31: Initializing runtime services
INFO: BL31: Preparing for EL3 exit to normal world
INFO: Entry point address = 0x37000000
INFO: SPSR = 0x3c9
U-Boot 2017.05-g1de155d (May 16 2017 - 13:46:54 -0400)poplar
Model: HiSilicon Poplar Development Board
BOARD: Hisilicon HI3798cv200 Poplar
DRAM: 1 GiB
MMC: Hisilicon DWMMC: 0
*** Warning - bad CRC, using default environment
In: serial@8b00000
Out: serial@8b00000
Err: serial@8b00000
Net: Net Initialization Skipped
No ethernet found.
Hit any key to stop autoboot: 0
poplar# mmc info
Device: Hisilicon DWMMC
Manufacturer ID: 15
OEM: 100
Name: 8WPD3
Tran Speed: 52000000
Rd Block Len: 512
MMC version 5.0
High Capacity: Yes
Capacity: 7.3 GiB
Bus Width: 8-bit
Erase Group Size: 512 KiB
HC WP Group Size: 8 MiB
User Capacity: 7.3 GiB WRREL
Boot Capacity: 4 MiB ENH
RPMB Capacity: 512 KiB ENH
poplar# printenv
arch=arm
baudrate=115200
board=poplar
board_name=poplar
boot_a_script=load ${devtype} ${devnum}:${distro_bootpart} ${scriptaddr} ${pref}
boot_efi_binary=load ${devtype} ${devnum}:${distro_bootpart} ${kernel_addr_r} ei
boot_extlinux=sysboot ${devtype} ${devnum}:${distro_bootpart} any ${scriptaddr}f
boot_net_usb_start=usb start
boot_prefixes=/ /boot/
boot_script_dhcp=boot.scr.uimg
boot_scripts=boot.scr.uimg boot.scr
boot_targets=usb0 mmc0 dhcp
bootcmd=run distro_bootcmd
bootcmd_dhcp=run boot_net_usb_start; if dhcp ${scriptaddr} ${boot_script_dhcp};;
bootcmd_mmc0=setenv devnum 0; run mmc_boot
bootcmd_usb0=setenv devnum 0; run usb_boot
bootdelay=2
cpu=armv8
distro_bootcmd=for target in ${boot_targets}; do run bootcmd_${target}; done
efi_dtb_prefixes=/ /dtb/ /dtb/current/
env_mmc_blknum=0xF0000
env_mmc_nblks=0x80
fdt_addr_r=0x32200000
fdtcontroladdr=3df4faf0
kernel_addr_r=0x30000000
load_efi_dtb=load ${devtype} ${devnum}:${distro_bootpart} ${fdt_addr_r} ${prefi}
loader_mmc_blknum=0x0
loader_mmc_nblks=0x780
mmc_boot=if mmc dev ${devnum}; then setenv devtype mmc; run scan_dev_for_boot_pi
pxefile_addr_r=0x32000000
ramdisk_addr_r=0x32400000
scan_dev_for_boot=echo Scanning ${devtype} ${devnum}:${distro_bootpart}...; for;
scan_dev_for_boot_part=part list ${devtype} ${devnum} -bootable devplist; env ee
scan_dev_for_efi=setenv efi_fdtfile ${fdtfile}; for prefix in ${efi_dtb_prefixee
scan_dev_for_extlinux=if test -e ${devtype} ${devnum}:${distro_bootpart} ${prefi
scan_dev_for_scripts=for script in ${boot_scripts}; do if test -e ${devtype} ${e
scriptaddr=0x32000000
soc=hi3798cv200
stderr=serial@8b00000
stdin=serial@8b00000
stdout=serial@8b00000
usb_boot=usb start; if usb dev ${devnum}; then setenv devtype usb; run scan_devi
vendor=hisilicon