Radek

Use an SD card less than or equal to 8GB. Format the card to FAT32. Update TFT to the latest FW. https://github.com/bigtreetech/BIGTREETECH-TouchScreenFirmware

A 64G SD card formatted to 1G is not the same as a 1G SD card. SD cards are divided by type into 3 groups according to the standard. SD...

Are you interested in testing a possible solution to this problem? If so, write in this thread. A programmer is looking for someone with this problem to test the fix....

Check the thermal protection settings in Marlin

At 12 V, too large currents flow. There may be a problem with the connectors or the fuse. The switching transistor can also overheat. It would be better to use...

The problem will be on SKR If you can, return it to the seller. If this is not possible, use an external MOSFET to power the bed

This is the current connection, or do you want to connect it like this?

By connecting an external Mosfet, you have the option of fitting better cooling and you do not risk damaging the SKR board. If one of the Mosfet transistors is defective,...

Then it's easy. You can bypass the faulty mosfet and connect pin P2.05 from the processor directly to the external mosfet.