I don't find sd card firmware directly from halong it seems that their miners are automatically update.
If you have SD card slot you can flash it with different firmware like braiins OS.
You can check their official thread from here
https://bitcointalk.org/index.php?topic=5036844.0But if you don't have an SD card slot I think you can't flash it with Braiins OS but try to flash it in webGUI using Braiins OS I think they have a firmware where you can use to update your firmware to Braiins OS or through SSH you just need to have access to SSH of your dragonmint t1 This is permanent method and you can't roll back it to the original firmware.