from what I could find, the specs are identical except for 2 changes: the replacement of the 9250 with 2 chips (the MPU6050 and the MAG3110); and the upgrade of the battery (150 mAh to 600 mAh)
Fire vs Gray?
I am considering getting a M5Stack to teach programming and robotics to kids, and noticed that a new version is coming out tomorrow: the M5Stack Fire. Looking at the specs, it looks like the new version has a better battery and that the MPU9250 that was included in the "gray" version was replaced with a MPU6050 and MAG3110 to provide the same capabilities. Any idea why? Was there a problem with the 9250 devices?
As a separate question, can you suggest a simple robotics tutorial for the M5Stack?