after having lot of problems due to memory lack, I changed all my variables to optimize it, byte for int, etc.
Yesterday I updated the SDK and drivers of my Arduino Ethernet, I was trying to solve an error and I couldn't find any other solution so far. It worked and I stepped forward on it, but still frozen.
Today I realised, what was working in previous version it doesn't anymore.
When I mapped byte to int in a for loop, it worked so far, but it doesn't anymore, and compiler doesn't advice it.