Temperture limit with commands M104/M109 different from screen limit (no replies)

Hello,

I got this problem and I'm unable to find a solution by myself. I want to set up the hotend temperature up to 300 degree but the firmware limits the commands M104 and M109 returning a max temperature of 284. I also cannot run PID for higher temperatures.

But I set the MAXTEMP in the firmware to 320 degree and using the screen I can reach set 305 as expected, 320 an 15 degree overshoot.

This is the serial output when using the screen. I mean the standard LCD screen, not an external TFT.

Recv:  T:15.94 /0.00 B:17.03 /0.00 @:0 B@:0
Recv:  T:16.09 /0.00 B:17.19 /0.00 @:0 B@:0
Recv:  T:16.09 /0.00 B:17.19 /0.00 @:0 B@:0
Recv:  T:15.94 /0.00 B:17.19 /0.00 @:0 B@:0
Recv:  T:16.09 /0.00 B:16.72 /0.00 @:0 B@:0
Recv:  T:17.81 /305.00 B:16.87 /0.00 @:127 B@:0
Recv:  T:17.19 /305.00 B:16.72 /0.00 @:127 B@:0
Recv:  T:17.34 /305.00 B:17.03 /0.00 @:127 B@:0
Recv:  T:18.91 /305.00 B:17.03 /0.00 @:127 B@:0
Recv:  T:21.72 /305.00 B:16.72 /0.00 @:127 B@:0
Recv:  T:24.69 /305.00 B:16.56 /0.00 @:127 B@:0
Recv:  T:27.50 /305.00 B:16.56 /0.00 @:127 B@:0
Recv:  T:31.04 /305.00 B:16.87 /0.00 @:127 B@:0
Recv:  T:35.33 /305.00 B:16.87 /0.00 @:127 B@:0

And here is the output when sending commands thorugh an octopront setup.

2021-03-08 19:06:24,144 - Recv:  T:17.81 /0.00 B:17.34 /0.00 @:0 B@:0
2021-03-08 19:06:26,144 - Recv:  T:17.81 /0.00 B:17.50 /0.00 @:0 B@:0
2021-03-08 19:06:26,462 - Send: M104 S300
2021-03-08 19:06:26,473 - Recv: ok
2021-03-08 19:06:28,144 - Recv:  T:17.97 /284.00 B:17.50 /0.00 @:127 B@:0
2021-03-08 19:06:30,144 - Recv:  T:18.28 /284.00 B:17.34 /0.00 @:127 B@:0
2021-03-08 19:06:32,144 - Recv:  T:19.22 /284.00 B:17.50 /0.00 @:127 B@:0
2021-03-08 19:06:34,144 - Recv:  T:20.62 /284.00 B:17.66 /0.00 @:127 B@:0
2021-03-08 19:06:36,144 - Recv:  T:22.97 /284.00 B:17.66 /0.00 @:127 B@:0
2021-03-08 19:06:38,144 - Recv:  T:25.91 /284.00 B:17.66 /0.00 @:127 B@:0

Send: M109 S300
Recv:  T:18.28 /284.00 B:17.19 /0.00 @:0 B@:0 W:?
Recv:  T:18.44 /284.00 B:17.19 /0.00 @:127 B@:0 W:?
Recv:  T:18.44 /284.00 B:16.72 /0.00 @:127 B@:0

I'm using marlin 2.0 with an skr1.3 board. I configured the firmware from scratch but I have been unable to find what is causing this.

What's the difference between serial command and using screen? Why are limits different and how do I change this?

Any help is welcome.