Trying tô increse maximum temperatura of the hotend

Hi everyone!
I have a Reprap Prusa printer, and I am trying to increase the maximum temperatura of the hotend, but did not succeed, yet.
I have noticed that in Marlin this temperature is set to be 250 degrees Celsius, but, effectively, It is just allowed to reach 235.
Is there any way to set this temperature higher? Maybe 255 degrees?
Thanks!

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Let nothing frighten you,
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This is related to your hardware

The thermistor type defines the highest readable temperature

Eg type 1 thermistor [github.com]
The highest value in the table is 320

Next you have #define HOTEND_OVERSHOOT 15 // (°C) Forbid temperatures over MAXTEMP - OVERSHOOT
You need some overshoot so firmware can tell its over the temperature you set

so the max usable temperature is 320-15 = 305

This can be further reduced with #define HEATER_0_MAXTEMP 275
eg if your hotend has PTFE in the heated zone, you must limit the max temperature down to safer limits.

Yes!
I have a PTFE inside the heatbreak.
May I modify maximum temperature do 265 degrees C in order to reach 250?
Thanks again!

I also see that I can´t modify these parameters, like maxtemp, for example, in Marlin.
I just dont know why, but whenever I change in Marlin, and transfer the firmware to the printer, these parameters do not change.
The only way I can change is through pronterface.
What are the G-Codes to change HEATER_0_MAXTEMP?
Thanks.