diff --git a/src/components/configuration/constants.test.ts b/src/components/configuration/constants.test.ts
new file mode 100644
index 000000000..e6b4b2fde
--- /dev/null
+++ b/src/components/configuration/constants.test.ts
@@ -0,0 +1,33 @@
+import { describe, it, expect } from 'vitest';
+import { REGION_OPTIONS } from './constants';
+
+// Guards against RegionCode drift from meshtastic/protobufs config.proto (#3927).
+// When upstream adds a RegionCode value, extend REGION_OPTIONS and bump the max here.
+describe('REGION_OPTIONS', () => {
+  const HIGHEST_REGION_CODE = 37; // ITU2_125CM — keep in sync with config.proto enum RegionCode
+
+  it('covers contiguous RegionCode values 0..HIGHEST_REGION_CODE with no gaps or dupes', () => {
+    const values = REGION_OPTIONS.map((o) => o.value).sort((a, b) => a - b);
+    expect(values).toEqual(Array.from({ length: HIGHEST_REGION_CODE + 1 }, (_, i) => i));
+  });
+
+  it('every option has a non-empty "NAME - description" label', () => {
+    for (const o of REGION_OPTIONS) {
+      expect(o.label).toMatch(/^\S+ - .+/);
+    }
+  });
+
+  it('uses the upstream enum name ITU2_2M for value 28 (not the old ITU23_2M)', () => {
+    const v28 = REGION_OPTIONS.find((o) => o.value === 28);
+    expect(v28?.label.startsWith('ITU2_2M -')).toBe(true);
+  });
+
+  it('includes the ITU amateur regions 33-37 added in #3927', () => {
+    const byValue = new Map(REGION_OPTIONS.map((o) => [o.value, o.label]));
+    expect(byValue.get(33)?.startsWith('ITU3_2M')).toBe(true);
+    expect(byValue.get(34)?.startsWith('ITU1_70CM')).toBe(true);
+    expect(byValue.get(35)?.startsWith('ITU2_70CM')).toBe(true);
+    expect(byValue.get(36)?.startsWith('ITU3_70CM')).toBe(true);
+    expect(byValue.get(37)?.startsWith('ITU2_125CM')).toBe(true);
+  });
+});
diff --git a/src/components/configuration/constants.ts b/src/components/configuration/constants.ts
index 809fff71f..ed9c16f92 100644
--- a/src/components/configuration/constants.ts
+++ b/src/components/configuration/constants.ts
@@ -117,11 +117,16 @@ export const REGION_OPTIONS: RegionOption[] = [
   { value: 25, label: 'NP_865 - Nepal 865MHz' },
   { value: 26, label: 'BR_902 - Brazil 902MHz' },
   { value: 27, label: 'ITU1_2M - ITU Region 1 Amateur 2m (144-146 MHz)' },
-  { value: 28, label: 'ITU23_2M - ITU Region 2/3 Amateur 2m (144-148 MHz)' },
+  { value: 28, label: 'ITU2_2M - ITU Region 2 Amateur 2m (144-148 MHz)' },
   { value: 29, label: 'EU_866 - European Union 866MHz SRD' },
   { value: 30, label: 'EU_874 - European Union 874MHz SRD' },
   { value: 31, label: 'EU_917 - European Union 917MHz SRD' },
-  { value: 32, label: 'EU_N_868 - European Union 868MHz Narrow' }
+  { value: 32, label: 'EU_N_868 - European Union 868MHz Narrow' },
+  { value: 33, label: 'ITU3_2M - ITU Region 3 Amateur 2m (144-148 MHz)' },
+  { value: 34, label: 'ITU1_70CM - ITU Region 1 Amateur 70cm (430-440 MHz)' },
+  { value: 35, label: 'ITU2_70CM - ITU Region 2 Amateur 70cm (420-450 MHz, check local law)' },
+  { value: 36, label: 'ITU3_70CM - ITU Region 3 Amateur 70cm (430-450 MHz, check local law)' },
+  { value: 37, label: 'ITU2_125CM - ITU Region 2 Amateur 1.25m (220-225 MHz, check local law)' }
 ];
 
 // Config.LoRaConfig.FEM_LNA_Mode (firmware >= v2.7.20, meshtastic/firmware#9809).
diff --git a/src/server/services/deviceBackupService.ts b/src/server/services/deviceBackupService.ts
index e93251a90..d1a654939 100644
--- a/src/server/services/deviceBackupService.ts
+++ b/src/server/services/deviceBackupService.ts
@@ -175,7 +175,18 @@ const EnumMappings: Record<string, Record<number, string>> = {
     23: 'KZ_433',
     24: 'KZ_863',
     25: 'NP_865',
-    26: 'BR_902'
+    26: 'BR_902',
+    27: 'ITU1_2M',
+    28: 'ITU2_2M',
+    29: 'EU_866',
+    30: 'EU_874',
+    31: 'EU_917',
+    32: 'EU_N_868',
+    33: 'ITU3_2M',
+    34: 'ITU1_70CM',
+    35: 'ITU2_70CM',
+    36: 'ITU3_70CM',
+    37: 'ITU2_125CM'
   },
   DetectionTriggerType: {
     0: 'NONE',
diff --git a/src/utils/loraFrequency.test.ts b/src/utils/loraFrequency.test.ts
index 4939934d2..8ca83d841 100644
--- a/src/utils/loraFrequency.test.ts
+++ b/src/utils/loraFrequency.test.ts
@@ -138,6 +138,26 @@ describe('calculateLoRaFrequency', () => {
     });
   });
 
+  describe('ITU amateur regions added in RegionCode 33-37 (#3927)', () => {
+    // freqStart from firmware RadioInterface.cpp (develop / firmware#10627).
+    // Slot 0 at 250 kHz = freqStart + 0.125 MHz.
+    it('ITU3_2M (region 33): freqStart 144.0 → slot 0 = 144.125 MHz', () => {
+      expect(calculateLoRaFrequency(33, 1, 0, 0)).toBe('144.125 MHz');
+    });
+    it('ITU1_70CM (region 34): freqStart 430.0 → slot 0 = 430.125 MHz', () => {
+      expect(calculateLoRaFrequency(34, 1, 0, 0)).toBe('430.125 MHz');
+    });
+    it('ITU2_70CM (region 35): freqStart 420.0 → slot 0 = 420.125 MHz', () => {
+      expect(calculateLoRaFrequency(35, 1, 0, 0)).toBe('420.125 MHz');
+    });
+    it('ITU3_70CM (region 36): freqStart 430.0 → slot 0 = 430.125 MHz', () => {
+      expect(calculateLoRaFrequency(36, 1, 0, 0)).toBe('430.125 MHz');
+    });
+    it('ITU2_125CM (region 37): freqStart 220.0 → slot 0 = 220.125 MHz', () => {
+      expect(calculateLoRaFrequency(37, 1, 0, 0)).toBe('220.125 MHz');
+    });
+  });
+
   describe('Override frequency', () => {
     it('should use override frequency when set', () => {
       const result = calculateLoRaFrequency(1, 21, 915.0, 0);
diff --git a/src/utils/loraFrequency.ts b/src/utils/loraFrequency.ts
index 2d10edf07..0f5f30218 100644
--- a/src/utils/loraFrequency.ts
+++ b/src/utils/loraFrequency.ts
@@ -73,11 +73,16 @@ export function calculateLoRaFrequency(
     25: [865.0, 868.0],      // NP_865: 865-868 MHz
     26: [902.0, 907.5],      // BR_902: 902-907.5 MHz
     27: [144.0, 146.0],      // ITU1_2M: ITU Region 1 Amateur 2m
-    28: [144.0, 148.0],      // ITU23_2M: ITU Region 2/3 Amateur 2m
+    28: [144.0, 148.0],      // ITU2_2M: ITU Region 2 Amateur 2m
     29: [865.6, 867.6],      // EU_866: EU 866MHz SRD (2.5% duty)
     30: [873.4, 876.0],      // EU_874: EU 874MHz SRD (Decision 2022/172 Band 1, awaiting firmware)
     31: [917.4, 919.4],      // EU_917: EU 917MHz SRD (Decision 2022/172 Band 4, awaiting firmware)
-    32: [869.4, 869.65]      // EU_N_868: EU 868MHz Narrow (mandates LITE/NARROW preset)
+    32: [869.4, 869.65],     // EU_N_868: EU 868MHz Narrow (mandates LITE/NARROW preset)
+    33: [144.0, 148.0],      // ITU3_2M: ITU Region 3 Amateur 2m (firmware#10627, on develop / awaiting release)
+    34: [430.0, 440.0],      // ITU1_70CM: ITU Region 1 Amateur 70cm (firmware#10627, on develop / awaiting release)
+    35: [420.0, 450.0],      // ITU2_70CM: ITU Region 2 Amateur 70cm (firmware#10627, on develop / awaiting release)
+    36: [430.0, 450.0],      // ITU3_70CM: ITU Region 3 Amateur 70cm (firmware#10627, on develop / awaiting release)
+    37: [220.0, 225.0]       // ITU2_125CM: ITU Region 2 Amateur 1.25m (on develop / awaiting release)
   };
 
   if (!region || region === 0) {