In case this can help anyone else, I was having trouble with my SKR Pro V1.2 when trying to flash firmware. I formatted the included microSD several times, etc but could never get the flashy lights and firmware to flash. Also noted that the TFT would show ‘no printer attached’ when booted with the microSD inserted.
I found another microSD card, formatted it with a 500MB partition at FAT32 and it flashed right away. I can now also boot with the new microSD inserted and the printer does attach after the normal delay of 3-4 seconds.
I guess the card died in some strange way that made the SKR board not like it, while my linux PC still worked with it just fine…
I was re-installing PiOS today and had a similar problem. I was using the Windows Explorer Format function but it kept refusing to complete.
I ended up using the SD Associations formatter Here.
It still took changing the SD card adapter a couple times to find one that would stay active while the formatting was being done. (I’ve found that not all adapters work all the time, in all the USB ports, or with all SD cards. Go Figure!)
Once the was formatted (with the correct size and file system) I was able to write the data with no problem.