Not able to get this device flashed, either through physical reset or try-ethernet-once-than-nand options using windows.
RouterOS 6.47.8, connected via switch as documented.
-Renamed the initramfs-kernel file to rb.elf. rb.elf copied into the files folder
-rfc951=1 added to config.ini (complete file below)
-tiny pxe configured per install documentation
"Continue holding the reset button until you see TFTPd: DoReadFile: rb.elf in the Tiny PXE log window."