The Turing RK1 is a new Compute Module, made for the Turing Pi 2 board and with compability to the Nvidia Jetson cards in mind. While the board has some impressive specs ( https://docs.turingpi.com/docs/turing-rk1-specs-and-io-ports ) it had one small issue: The used Rockchip RK3588 needed a bootloader on its eMMC to be able to boot from an attached NVMe drive. As no isolated bootloader was available, most people flashed a whole OS onto the eMMC - just to be able to use the attched NVMe drive. This process can take quite a while via the Turing Pi 2 board ( e.g. 60 - 90 minutes: https://docs.turingpi.com/docs/turing-rk1-flashing-os ) it was never a good option.

Now there is finally a solution brought up by Mister gregordinary from the DietPi Forums - who deserves all the credit ( https://dietpi.com/forum/t/new-turingpi-rk1/19142/9 ):

On your local machine:

• Make yourself a working directory and open a terminal in that location.
• Download the u-boot apk: https://alpine-rk1.cfs.works/packages/main/aarch64/u-boot-turing-2024.04-r0.apk
• Open it with an archive utility and extract the following files into your working directory:
  a. idbloader.img
  b. u-boot.itb
• Create an .img file we’ll use later to flash the RK1: touch turing-rk1-uboot-only.img
• You should now have the idbloader.img, u-boot.itb, and turing-rk1-uboot-only.img in your working directory. From there, use dd to create our combined image:
  a. dd if=idbloader.img of=turing-rk1-uboot-only.img bs=512 seek=64
  b. dd if=u-boot.itb of=turing-rk1-uboot-only.img bs=512 seek=16384
• The resulting .img file can be used to flash the RK1 device through the Web UI or tpi utility.
• Once generated, this .img can be used "as is" to flash the other nodes after moving them to NVME.

With that generated file you can directly flash the eMMC and use any NVMe to boot from.

... and here is already a prepared file if you want to use it directly: turing-rk1-uboot-only.zip