Zero eMMC USB Boot Issue

Got my Zero, immediately went to try and enter maskrom mode because I didn’t want to use the Android pre-installed on the eMMC. Hold USB Boot button down as shown on wiki, but can never get Zadig to recognize the GX Chip, realized with device manager I wasn’t even recognizing a USB device, so I figured there was an issue. Saw that next step was getting a USB to TTL cable to hook up to the debug console. Few days to get that and set it up, now I’m able to see that when I power the Zero up it seems to start booting the android install from the eMMC, but when I hold the USB Boot button down and power it up I get this in my debug instead:

G12A:BL:0253b8:61aa2d;FEAT:E0F83180:2000;POC:D;RCY:0;USB:0;EMMC:0;READ:0;0.0
bl2_stage_init 0x01
bl2_stage_init 0x81
hw id: 0x0001 - pwm id 0x00
bl2_stage_init 0xc0
bl2_stage_init 0x02
L0:00000000
L1:00000703
L2:00008067
L3:04000000
S1:00000000
B2:00002000
B1:e0f83180
TE: 918458
BL2 Built : 15:21:48, Aug 28 2019. g12a g1bf2b53 - luan.yuan@droid15-sz
Board ID = 2
Set cpu clk to 24M
Set clk81 to 24M
CPU clk: 1200 MHz
Set clk81 to 166.6M
eMMC boot @ 0
sd/emmc cmd 17 arg 0x00000001 status 01df00df
sw8 f
DDR driver_vesion: LPDDR4_PHY_V_0_1_18 build time: Aug 28 2019 15:21:45
board id: 2
Load FIP HDR from eMMC, src: 0x00010200, des: 0xfffd0000, size: 0x00004000, part: 0
sd/emmc cmd 17 arg 0x00000081 status 01de000f
sdio read data fail
FIP HDR CHK: 0x00000065 ADDR 0xfffd0000
Load FIP HDR from eMMC, src: 0x00010200, des: 0xfffd0000, size: 0x00004000, part: 1
sd/emmc cmd 8 arg 0x00000000 status 01de000f
00000001
emmc swith 1 part fail
FIP HDR CHK: 0x00000065 ADDR 0xfffd0000
Load FIP HDR from eMMC, src: 0x00010200, des: 0xfffd0000, size: 0x00004000, part: 2
sd/emmc cmd 8 arg 0x00000000 status 01de000f
00000001
emmc swith 2 part fail
FIP HDR CHK: 0x00000065 ADDR 0xfffd0000
reset…

Any ideas for fixing from my end, or is this indicative of a hardware issue?

Make sure you really held that button. When done correctly you should only see one line similar to this in serial:

G12A:BL:0253b8:61aa2d;FEAT:E0F83180:2000;POC:D;RCY:0;USB:0;EMMC:0;READ:0;0.0

I’m very confident I held the button down, I could feel it depress when I was doing this, and I tried it multiple times to ensure the problem was repeatable. When I was sure I held the button down, I got the debug I posted above, and as long as I held the button down it would print to the “reset…” line, wait a few seconds, then start again at G12A… repeating the section I posted until I release the button. As soon as the button is released, the repeating in the debug stops (why I’m confident I was holding it as it did this multiple times), and it starts loading android from the eMMC.