So far I tested successfully:

- installed CM4 Lite, CM4 (+8GB eMMC), CM4 Lite with WiFi/BT,

- GbE ETH,
- 4-port USB hub 2.0 (connected keyboard, mouse, pendrive, USB Audio DAC),
- M.2 PCIe socket -> connected NVMe SSD drives Sandisk (2242 size, 3V3 @1.5A) and Kingston (2280 size 3V3@3A),
- Coral TPU (initially, not supported yet by CM4)
- USB-C (power/data),
- boot from USB-C,
- HDMI #0, HDMI #1,
- RESET button,
- power switch,
- 2-pin pwr connector,
- RTC + battery backup,
- temp. sensor,
- 2x status LEDs,
- buzzer,
- MIPI CSI cameras outputs (#0 & #1),
- overclocking CM4 up to 2.21 GHz,
- fan connector and dedicated heatsink with 5V fan,
- DAC + headphone amplifier,
- external eMMC BGA153 v5.1 IC chip (8GB FORESEE),
- @volumio (+ DAC + usb + eth),
- @LibreELEC (+ DAC + usb + eth),
- @MoodeAudio (initially, too long configuration),
- other OS (Raspbian, RiscOS),

TODO list:
- 4K HDMI,
- dual monitor (Full HD & 4K),
- HAT board (any original)
- Coral TPU & AI/ML apps (not supported yet, needed drivers)
- DSI LCD panel (display #0/#1 outputs)
- M.2 3V3 max. current

Fully assembled MirkoPC with installed SSD NVMe drive (2280 size):

Tested with SD Card:
And also with external eMMC BGA153 v5.1 IC memory: