My N1 had CM7 when starting this, should work with any ROM or recovery installed I think.
I followed steps from https://forum.xda-developers.com/sho....php?t=2667118 , instead using the Nexus One Carbon Kitkat ROM image.
Instead of installing android I used a usb boot image https://www.xda-developers.com/usb-b...recovery-fwul/ which became a must due to windows 10 not properly installing bootloader mode usb drivers.
My n1 was already unlocked and rooted, had CWM recovery and had CM7 running as said, so skipped those steps from the list.
I flashed 4EXT recovery from recovery.img file with 'fastboot flash recovery recovery.img' after downloading the image from https://forum.xda-developers.com/sho....php?t=1419813 using the "If you somehow lost the files" download link https://forum.xda-developers.com/nexus-one/development then partitioned the SD Card with a EXT4 with 2GB.
Black rose was a challenge, it did notwork in linux, had to manual install with fastboot, go to windows to configure custom, then back to linux to fastboot flash the custom image.
Main challenge was rebooting into recovery mode from fastboot at some point.
I had to flash 4EXT recovery again after blackrose partitioning and then booted into recovery with "fastboot boot recovery.img" then select to install the Carbon KitKat N1 ROM from SD Card and rebooted first time to carbon.
Had to share after so much strugle, hope it helps someone someday, maybe even myself if I forget how to do it after a few years