Unable to boot device into maskrom mode

Hello,

I am running Mac OS 10.14.3, trying to boot my Rock960c into maskrom mode to flash Debian onto the eMMC. (I have two boards, one with embedded eMMC and one with removable eMMC).

For my board, I hold down the maskrom button, then press the reset button. The board is connected to my Mac via USB-A to USB-C. When I run, lsusb, the device is not recognized:

2019-02-26 17:02:34.904 system_profiler[40159:744088] SPUSBDevice: IOCreatePlugInInterfaceForService failed 0xe00002be
2019-02-26 17:02:34.904 system_profiler[40159:744088] SPUSBDevice: IOCreatePlugInInterfaceForService failed 0xe00002be
2019-02-26 17:02:34.905 system_profiler[40159:744088] SPUSBDevice: IOCreatePlugInInterfaceForService failed 0xe00002be
2019-02-26 17:02:34.906 system_profiler[40159:744088] SPUSBDevice: IOCreatePlugInInterfaceForService failed 0xe00002be
2019-02-26 17:02:34.907 system_profiler[40159:744088] SPUSBDevice: IOCreatePlugInInterfaceForService failed 0xe00002be
Bus 128 Device 000: ID 05ac:8102 Apple Inc. iBridge DFR brightness  Serial: 000000000000
Bus 128 Device 000: ID 05ac:8302 Apple Inc. iBridge Display  Serial: 0000000000000000
Bus 128 Device 001: ID 05ac:027c Apple Inc. Apple Internal Keyboard / Trackpad  Serial: FM7836507N5HYYMAZ+ENN
Bus 128 Device 007: ID 05ac:5043 Apple Inc. Headset  Serial: 000000000000
Bus 128 Device 000: ID 05ac:8262 Apple Inc. iBridge ALS  Serial: 000000000000
Bus 128 Device 000: ID 05ac:8514 Apple Inc. iBridge FaceTime HD Camera (Built-in)  Serial: CC283955LK3J3Y328
Bus 128 Device 000: ID 05ac:8233 Apple Inc. iBridge  Serial: 0000000000000000
Bus 000 Device 001: ID 1d6b:XHCI
CITR Linux Foundation USB 3.1 Bus 
Bus 001 Device 001: ID 1d6b:CITR Linux Foundation USB 3.1 Bus 
Bus 000 Device 000: ID 05ac:8102 Apple Inc. iBridge Bus 

Is there a firmware that my Mac device needs to recognize Rock960 devices?

I think you probably want to look at this thread:

I was able to boot the device into maskrom mode using these instructions https://www.96boards.org/documentation/consumer/rock/installation/linux-mac-rkdeveloptool.md.html