I took an SD card from a Pi Zero that was lying on my desk and plugged it the new board.
Alas, the new board got stuck on a rainbow square pattern at boot time, with a distinctive little lightning bolt icon in the upper right corner of the screen, as shown below.
It turns out that the Raspberry Pi 3 B+ needs the most recent boot code as detailed on the Raspberry Pi forums:
If you have one of the latest PI 3B+ which won't boot and it keeps stuck on the rainbow screen, while also displaying the under voltage (lightening bolt) icon, then you are simply are using boot code that is too old. Please download the very latest version of Raspbian, or do an upgrade to it (e.g. with
sudo apt updateand
sudo apt upgrade).
Well it works
After this fix, I can confirm that the PiJack HAT works for the Raspberry Pi 3 Model B+, as illustrated below.
I thought I'd share this tip, in case others run into the same issue.
With WiFi networking enabled, an HDMI screen and a USB key plugged into the board, running some CPU stress tests makes the combined power consumption of the Pi and the HAT peak at 5.5W (1.1A@5V) with still plenty of headroom for more...