Sharpen blurry mipmaps in Unity

MipMapBiasAdjusterS.cs

using UnityEngine;
using System.Collections;

public class MipMapBiasAdjusterS : MonoBehaviour {

	[Header("Settings")]
	[Tooltip("A positive bias makes a texture appear extra blurry, while a negative bias sharpens the texture. Note that using large negative bias can reduce performance, so it's not recommended to use more than -0.5 negative bias.)")]
	public float _target = -2f;
	[Tooltip("Adjust all textures found in scene?")]
	public bool _allTexturesOnStart;

	[Header("References")]
	public Texture[] _texturesToAdjust;

	void Start()
	{
		if (_allTexturesOnStart)
		{
			foreach (Texture tex in (Texture[])Resources.FindObjectsOfTypeAll(typeof(Texture)))
			{
				tex.mipMapBias = _target;
			}
		}
	}
	
	[ContextMenu("Adjust")]
	public void Adjust()
	{
		foreach (Texture tex in _texturesToAdjust)
		{
			tex.mipMapBias = _target;
		}
	}

}