One of the most annoying missing features of the HiKey ARM54 board is the lack of a proper UART connection, to enable the same degree of boot information as other SoC systems..     There is a 4-pin/hole connection point, but no actual connector…    So, I had to get out the (mini) soldering iron, and magnifying goggles, and use a not-so-steady hand..

I managed to solder on three pin-type connectors, cut from a strip of a dozen or so, and then use female push-on connectors to the 1.8v USB/UART tail..

HiKey UART Connection

After this, I got a proper boot / console display (on /dev/ttyAMA0):

........
debug EMMC boot: print init OK
debug EMMC boot: send RST_N .
debug EMMC boot: start eMMC boot......
load fastboot1!
#PMU LDO15_REG_ADJ:0x00000054, STATUS3_LDO9_16:0x00000048
#PMU LDO22_REG:ADJ:0x00000057, STATUS4_LDO17_22:0x00000026
[BDID]boardid: 777 <7.7.7>
#select_hw_config, 58, board_id:0x0000002b
#select_hw_config, 71, array index:0
baudRate=115200, g_baudRate=115200
get_hw_config_int,hw_afreq:1200000.
get_efuse_value,efuse ATE_flag temp:0x02800000.
ATE PASS,ate flag value:0x00000001.
get_efuse_value,efuse acpu_freq change level:0xb6baeb00.
get_efuse_value,efuse afreq change level val:0x00000000.
get_efuse_value,efuse acpu_freq level:0xb6baeb00.
get_efuse_value,efuse acpu freq sys level:0x00000000.
###INFO###,soc_freq = hw_afreq, efuse_afreq:1200000,hw_afreq:1200000.
efuse ACPU 1.4G HPM:0.
efuse ACPU 1.2G HPM:0.
efuse ACPU 960M HPM:0.
fastboot: acpu_dvfs_init successful!
acpu_get_dvfs_volt,g_afreq_max_pro is :5▒▒acpu max freq:1200000.
acpu support freq num:5
volt:0x0000003a 0x0000003a 0x0000004a 0x0000005b 0x0000006b
acpu start prof:0x00000004
acpu magic:0x5a5ac5c5
#### success !!!!! set_acpu_freq: acpu support freq num is 5 and start is 4 .
get_ddr_type 1; (lpddr2: 0; lpddr3: 1)
ddr_init(): get_ddr_type: 1
 ddr freq: 800000
in lpddr3_init: mode: 0; freq_config: 800
...... etc.......

This is (IMHO) essential for proper development and testing, especially as this device (unlike the DragonBoard 410c) has a version of U-Boot available, and also supports UEFI..  https://github.com/96boards/documentation/wiki/HiKeyUEFI

So far, I have not been able to get a newer compiled Kernel to boot, but this UART console connection will help to get things working….

Robert Gadsdon.  July 11, 2015.