RPI3B+ USB boot failure, Drive not detected by bootcode.bin

Start with the Raspberry Pi boot modes documentation and compare boot-failed-bootcode_bin-only.log with boot-success-allfiles.log. Reproduce the minimal-SD setup with the Kingston SSD and external case; done means the drive is detected by bootcode.bin and the Pi boots with only the required SD files.

Hi!

I'm trying to boot my rPi 3B+ from a USB-attached SSD in an external case.
Drive: Kingston ssdNow V200 128GB SSD
Case: Kingston-provided SNA-DC/U fw:1.08

After reading a few other posts about USB boot issues, I tried a few ways to get it to work:

1. Try to boot without an SD card: FAIL, Never comes up.

2. Try to boot with only bootcode.bin and "timeout" file on the SD card: FAIL, see attached file boot-failed-bootcode_bin-only.log

3. Try to boot with full Boot files on SD card: PASS, see attached file boot-success-allfiles.log

Boot files where up to date as of this post (sudo rpi-update, and copied /boot to /boot-sd). I tried with nothing else than the drive connected to the Pi's USB ports, no change.

Related link: Raspberry Pi boot modes

What I would like: To boot with minimal files on the SD card, and the rest on the SSD.
Right now, ALL of /boot is mirrored on the SD card mounted as /boot-sd and it's working. I can live with that, but if it's supposed to work, I'm ready to help get it to work.

Thanks!
Martin

ve2mrx@rPi:~ $ uname -a
Linux rPi 4.14.93-v7+ #1191 SMP Wed Jan 16 11:53:33 GMT 2019 armv7l GNU/Linux

ve2mrx@rPi:~ $ lsblk
NAME        MAJ:MIN RM   SIZE RO TYPE MOUNTPOINT
sda           8:0    0 119.2G  0 disk
|-sda1        8:1    0  43.9M  0 part /boot
`-sda2        8:2    0  29.7G  0 part /
mmcblk0     179:0    0 970.5M  0 disk
`-mmcblk0p1 179:1    0 970.4M  0 part /boot-sd

ve2mrx@rPi:~ $ lsusb
Bus 001 Device 005: ID 11b0:6298 ATECH FLASH TECHNOLOGY
Bus 001 Device 004: ID 0424:7800 Standard Microsystems Corp.
Bus 001 Device 003: ID 0424:2514 Standard Microsystems Corp. USB 2.0 Hub
Bus 001 Device 002: ID 0424:2514 Standard Microsystems Corp. USB 2.0 Hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

boot-failed-bootcode_bin-only.log
boot-success-allfiles.log