diff --git a/src/BizHawk.Emulation.Cores/Consoles/Nintendo/GBHawkLink/GBHawkLink.IDebuggable.cs b/src/BizHawk.Emulation.Cores/Consoles/Nintendo/GBHawkLink/GBHawkLink.IDebuggable.cs
index 56e271f6cf..80d0a335ea 100644
--- a/src/BizHawk.Emulation.Cores/Consoles/Nintendo/GBHawkLink/GBHawkLink.IDebuggable.cs
+++ b/src/BizHawk.Emulation.Cores/Consoles/Nintendo/GBHawkLink/GBHawkLink.IDebuggable.cs
@@ -1,6 +1,6 @@
 using System;
 using System.Collections.Generic;
-using System.Linq;
+
 using BizHawk.Common.StringExtensions;
 using BizHawk.Emulation.Common;
 
@@ -8,27 +8,22 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBHawkLink
 {
 	public partial class GBHawkLink : IDebuggable
 	{
+		private const string PFX_L = "Left ";
+
+		private const string PFX_R = "Right ";
+
 		public IDictionary<string, RegisterValue> GetCpuFlagsAndRegisters()
 		{
-			var left = L.GetCpuFlagsAndRegisters()
-				.Select(reg => new KeyValuePair<string, RegisterValue>("Left " + reg.Key, reg.Value));
-
-			var right = R.GetCpuFlagsAndRegisters()
-				.Select(reg => new KeyValuePair<string, RegisterValue>("Right " + reg.Key, reg.Value));
-
-			return left.Union(right).ToDictionary(pair => pair.Key, pair => pair.Value);
+			Dictionary<string, RegisterValue> dict = new();
+			foreach (var ref in L.GetCpuFlagsAndRegisters()) dict[PFX_L + reg.Key] = reg.Value;
+			foreach (var ref in R.GetCpuFlagsAndRegisters()) dict[PFX_R + reg.Key] = reg.Value;
+			return dict;
 		}
 
 		public void SetCpuRegister(string register, int value)
 		{
-			if (register.StartsWithOrdinal("Left "))
-			{
-				L.SetCpuRegister(register.Replace("Left ", ""), value);
-			}
-			else if (register.StartsWithOrdinal("Right "))
-			{
-				R.SetCpuRegister(register.Replace("Right ", ""), value);
-			}
+			if (register.StartsWithOrdinal(PFX_L)) L.SetCpuRegister(register.Substring(PFX_L.Length), value);
+			else if (register.StartsWithOrdinal(PFX_R)) R.SetCpuRegister(register.Substring(PFX_R.Length), value);
 		}
 
 		public IMemoryCallbackSystem MemoryCallbacks { get; } = new MemoryCallbackSystem(new[] { "System Bus" });
diff --git a/src/BizHawk.Emulation.Cores/Consoles/Nintendo/GBHawkLink3x/GBHawkLink3x.IDebuggable.cs b/src/BizHawk.Emulation.Cores/Consoles/Nintendo/GBHawkLink3x/GBHawkLink3x.IDebuggable.cs
index e4e6efbbec..7ac2bdf049 100644
--- a/src/BizHawk.Emulation.Cores/Consoles/Nintendo/GBHawkLink3x/GBHawkLink3x.IDebuggable.cs
+++ b/src/BizHawk.Emulation.Cores/Consoles/Nintendo/GBHawkLink3x/GBHawkLink3x.IDebuggable.cs
@@ -1,6 +1,6 @@
 using System;
 using System.Collections.Generic;
-using System.Linq;
+
 using BizHawk.Common.StringExtensions;
 using BizHawk.Emulation.Common;
 
@@ -8,34 +8,26 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBHawkLink3x
 {
 	public partial class GBHawkLink3x : IDebuggable
 	{
+		private const string PFX_C = "Center ";
+
+		private const string PFX_L = "Left ";
+
+		private const string PFX_R = "Right ";
+
 		public IDictionary<string, RegisterValue> GetCpuFlagsAndRegisters()
 		{
-			var left = L.GetCpuFlagsAndRegisters()
-				.Select(reg => new KeyValuePair<string, RegisterValue>("Left " + reg.Key, reg.Value));
-
-			var center = C.GetCpuFlagsAndRegisters()
-				.Select(reg => new KeyValuePair<string, RegisterValue>("Center " + reg.Key, reg.Value));
-
-			var right = R.GetCpuFlagsAndRegisters()
-				.Select(reg => new KeyValuePair<string, RegisterValue>("Right " + reg.Key, reg.Value));
-
-			return left.Union(center).Union(right).ToDictionary(pair => pair.Key, pair => pair.Value);
+			Dictionary<string, RegisterValue> dict = new();
+			foreach (var ref in L.GetCpuFlagsAndRegisters()) dict[PFX_L + reg.Key] = reg.Value;
+			foreach (var ref in C.GetCpuFlagsAndRegisters()) dict[PFX_C + reg.Key] = reg.Value;
+			foreach (var ref in R.GetCpuFlagsAndRegisters()) dict[PFX_R + reg.Key] = reg.Value;
+			return dict;
 		}
 
 		public void SetCpuRegister(string register, int value)
 		{
-			if (register.StartsWithOrdinal("Left "))
-			{
-				L.SetCpuRegister(register.Replace("Left ", ""), value);
-			}
-			else if (register.StartsWithOrdinal("Center "))
-			{
-				C.SetCpuRegister(register.Replace("Center ", ""), value);
-			}
-			else if (register.StartsWithOrdinal("Right "))
-			{
-				R.SetCpuRegister(register.Replace("Right ", ""), value);
-			}
+			if (register.StartsWithOrdinal(PFX_C)) C.SetCpuRegister(register.Substring(PFX_C.Length), value);
+			else if (register.StartsWithOrdinal(PFX_L)) L.SetCpuRegister(register.Substring(PFX_L.Length), value);
+			else if (register.StartsWithOrdinal(PFX_R)) R.SetCpuRegister(register.Substring(PFX_R.Length), value);
 		}
 
 		public IMemoryCallbackSystem MemoryCallbacks { get; } = new MemoryCallbackSystem(new[] { "System Bus" });
diff --git a/src/BizHawk.Emulation.Cores/Consoles/Nintendo/GBHawkLink4x/GBHawkLink4x.IDebuggable.cs b/src/BizHawk.Emulation.Cores/Consoles/Nintendo/GBHawkLink4x/GBHawkLink4x.IDebuggable.cs
index eacf34597b..bd093f37fa 100644
--- a/src/BizHawk.Emulation.Cores/Consoles/Nintendo/GBHawkLink4x/GBHawkLink4x.IDebuggable.cs
+++ b/src/BizHawk.Emulation.Cores/Consoles/Nintendo/GBHawkLink4x/GBHawkLink4x.IDebuggable.cs
@@ -1,6 +1,6 @@
 using System;
 using System.Collections.Generic;
-using System.Linq;
+
 using BizHawk.Common.StringExtensions;
 using BizHawk.Emulation.Common;
 
@@ -8,41 +8,30 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBHawkLink4x
 {
 	public partial class GBHawkLink4x : IDebuggable
 	{
+		private const string PFX_A = "A ";
+
+		private const string PFX_B = "B ";
+
+		private const string PFX_C = "C ";
+
+		private const string PFX_D = "D ";
+
 		public IDictionary<string, RegisterValue> GetCpuFlagsAndRegisters()
 		{
-			var a = A.GetCpuFlagsAndRegisters()
-				.Select(reg => new KeyValuePair<string, RegisterValue>("A " + reg.Key, reg.Value));
-
-			var b = B.GetCpuFlagsAndRegisters()
-				.Select(reg => new KeyValuePair<string, RegisterValue>("B " + reg.Key, reg.Value));
-
-			var c = C.GetCpuFlagsAndRegisters()
-				.Select(reg => new KeyValuePair<string, RegisterValue>("C " + reg.Key, reg.Value));
-
-			var d = D.GetCpuFlagsAndRegisters()
-				.Select(reg => new KeyValuePair<string, RegisterValue>("D " + reg.Key, reg.Value));
-
-			return a.Union(b).Union(c).Union(d).ToDictionary(pair => pair.Key, pair => pair.Value);
+			Dictionary<string, RegisterValue> dict = new();
+			foreach (var ref in A.GetCpuFlagsAndRegisters()) dict[PFX_A + reg.Key] = reg.Value;
+			foreach (var ref in B.GetCpuFlagsAndRegisters()) dict[PFX_B + reg.Key] = reg.Value;
+			foreach (var ref in C.GetCpuFlagsAndRegisters()) dict[PFX_C + reg.Key] = reg.Value;
+			foreach (var ref in D.GetCpuFlagsAndRegisters()) dict[PFX_D + reg.Key] = reg.Value;
+			return dict;
 		}
 
 		public void SetCpuRegister(string register, int value)
 		{
-			if (register.StartsWithOrdinal("A "))
-			{
-				A.SetCpuRegister(register.Replace("A ", ""), value);
-			}
-			else if (register.StartsWithOrdinal("B "))
-			{
-				B.SetCpuRegister(register.Replace("B ", ""), value);
-			}
-			else if (register.StartsWithOrdinal("C "))
-			{
-				C.SetCpuRegister(register.Replace("C ", ""), value);
-			}
-			else if (register.StartsWithOrdinal("D "))
-			{
-				D.SetCpuRegister(register.Replace("D ", ""), value);
-			}
+			if (register.StartsWithOrdinal(PFX_A)) A.SetCpuRegister(register.Substring(PFX_A.Length), value);
+			else if (register.StartsWithOrdinal(PFX_B)) B.SetCpuRegister(register.Substring(PFX_B.Length), value);
+			else if (register.StartsWithOrdinal(PFX_C)) C.SetCpuRegister(register.Substring(PFX_C.Length), value);
+			else if (register.StartsWithOrdinal(PFX_D)) D.SetCpuRegister(register.Substring(PFX_D.Length), value);
 		}
 
 		public IMemoryCallbackSystem MemoryCallbacks { get; } = new MemoryCallbackSystem(new[] { "System Bus" });