Prepare fresh micro-SD card for MOX: only 1 out of 3 documented methods succeed

I’ve had a MOX (module A, without prepared micro-SD card) since the crowd-funding campaign, but only started using it now. So I took a micro-SD card, and started from here: https://docs.turris.cz/basics/first-setup/mox_cpu_only/. As I understand it, there are three methods to prepare the micro-SD card:

  1. place mox-medkit-latest image+md5sum (taken from https://repo.turris.cz/hbs/medkit/) on a USB stick and boot in rescue mode 4
  2. place mox-medkit-latest image+md5sum on the micro-SD card (formatted in either ext4, fat32, or brtfs) and boot in rescue mode 4
  3. prepare the micro-SD card on a Linux machine following these instructions: https://doc.turris.cz/doc/en/howto/mox_microsd_card

However, only method 1 worked for me, while to two others failed: the MOX never left rescue mode 4 (kept blinking, micro-SD card did not contain the extracted OS) (method 2), or the MOX did not complete the boot process (led was not blinking but just on, no heart beat) (method 3). The rescue mode documentation was found here: https://docs.turris.cz/hw/mox/rescue_modes/.

I noticed that the micro-SD card after method 1 did not have any label (or was blank), while with method 3 it was called turris. Not sure if that has anything to do with it. I prepared method 3 on an Arch Linux box, using a v5.7.2 kernel with btrfs v5.6.1 (is it possible I should use older kernel/btrfs versions to format the sd-cards?).

Not that it really matters to me at this point any longer (my MOX is up and running, but only after first spending quite a bit of time on methods 2 and 3 before trying method 1), but I was wondering if others actually managed to get methods 2 and 3 to work, and if yes, what did they do differently? Is it possible that there are some steps missing in the docs at both https://doc.turris.cz/doc/en/howto/mox_microsd_card and https://docs.turris.cz/hw/mox/rescue_modes/?