diff --git a/RouterOSAssistant/Core/Networking/RouterOSCliParser.swift b/RouterOSAssistant/Core/Networking/RouterOSCliParser.swift
index eec87e7..fd71d84 100644
--- a/RouterOSAssistant/Core/Networking/RouterOSCliParser.swift
+++ b/RouterOSAssistant/Core/Networking/RouterOSCliParser.swift
@@ -6,7 +6,7 @@ enum RouterOSCliParser {
     /// Parses `/system resource print` output (colon-separated "key: value" lines).
     static func parseDeviceInfo(_ raw: String) -> RouterDeviceInfo {
         var fields: [String: String] = [:]
-        for line in raw.split(separator: "\n") {
+        for line in raw.split(whereSeparator: \.isNewline) {
             guard let colonIndex = line.firstIndex(of: ":") else { continue }
             let key = String(line[line.startIndex..<colonIndex]).trimmingCharacters(in: .whitespaces)
             let value = String(line[line.index(after: colonIndex)...]).trimmingCharacters(in: .whitespaces)
@@ -21,8 +21,13 @@ enum RouterOSCliParser {
     }
 
     /// Parses `/interface print terse` output (one line per interface, `key=value` pairs).
+    ///
+    /// Splits on any newline-like character, not just "\n" — a real hEX device's SSH output
+    /// turned out not to split on bare "\n", collapsing every interface into a single "line"
+    /// whose repeated keys (name=, type=, ...) then overwrote each other in the fields
+    /// dictionary, leaving only the last interface (`lo`) in the result. Found via live testing.
     static func parseInterfaces(_ raw: String) -> [NetworkInterface] {
-        raw.split(separator: "\n").compactMap { line in
+        raw.split(whereSeparator: \.isNewline).compactMap { line in
             let fields = keyValues(from: String(line))
             guard let name = fields["name"] else { return nil }
             return NetworkInterface(
diff --git a/RouterOSAssistant/Features/Wizard/Steps/Setup/SetupView.swift b/RouterOSAssistant/Features/Wizard/Steps/Setup/SetupView.swift
index e388b98..492134c 100644
--- a/RouterOSAssistant/Features/Wizard/Steps/Setup/SetupView.swift
+++ b/RouterOSAssistant/Features/Wizard/Steps/Setup/SetupView.swift
@@ -21,11 +21,11 @@ struct SetupView: View {
                 } else {
                     switch viewModel.step {
                     case .wan:
-                        WanStepView(viewModel: viewModel, availableInterfaces: connectionService.interfaces)
+                        WanStepView(viewModel: viewModel, availableInterfaces: configurableInterfaces)
                     case .lan:
-                        LanStepView(viewModel: viewModel, availableInterfaces: connectionService.interfaces)
+                        LanStepView(viewModel: viewModel, availableInterfaces: configurableInterfaces)
                     case .vlan:
-                        VlanStepView(viewModel: viewModel, availableInterfaces: connectionService.interfaces)
+                        VlanStepView(viewModel: viewModel, availableInterfaces: configurableInterfaces)
                     case .wifi:
                         WifiStepView(viewModel: viewModel)
                     case .firewall:
@@ -37,9 +37,17 @@ struct SetupView: View {
             }
         }
         .onAppear {
-            viewModel.prepareDefaults(from: connectionService.interfaces)
+            viewModel.prepareDefaults(from: configurableInterfaces)
         }
     }
+
+    /// Loopback is never something a person should pick as WAN/LAN/VLAN base interface —
+    /// excluded here (not just via defaults) so a parsing hiccup elsewhere can't offer it as
+    /// a selectable option, which on a real hEX device caused every WAN/firewall command to
+    /// silently reference "lo" instead of the real WAN port. Found via live testing.
+    private var configurableInterfaces: [NetworkInterface] {
+        connectionService.interfaces.filter { $0.type.lowercased() != "loopback" }
+    }
 }
 
 #Preview {
diff --git a/RouterOSAssistantTests/RouterOSCliParserTests.swift b/RouterOSAssistantTests/RouterOSCliParserTests.swift
index 1f12d31..1060607 100644
--- a/RouterOSAssistantTests/RouterOSCliParserTests.swift
+++ b/RouterOSAssistantTests/RouterOSCliParserTests.swift
@@ -34,4 +34,22 @@ final class RouterOSCliParserTests: XCTestCase {
         XCTAssertFalse(interfaces[1].running)
         XCTAssertTrue(interfaces[1].disabled)
     }
+
+    /// Regression test for a real bug found on a physical hEX device: its SSH output didn't
+    /// split on bare "\n", collapsing every interface into one "line" whose repeated keys
+    /// (name=, type=, ...) overwrote each other, leaving only the last interface ("lo").
+    func testParseInterfacesHandlesCarriageReturnLineEndings() {
+        let raw = [
+            "0 R  name=ether1 default-name=ether1 type=ether mtu=1500",
+            "1 RS name=ether2 default-name=ether2 type=ether mtu=1500",
+            "5 R  comment=defconf name=bridge type=bridge mtu=auto",
+            "6 R  name=lo type=loopback mtu=65536"
+        ].joined(separator: "\r\n")
+
+        let interfaces = RouterOSCliParser.parseInterfaces(raw)
+
+        XCTAssertEqual(interfaces.count, 4)
+        XCTAssertEqual(interfaces.map(\.name), ["ether1", "ether2", "bridge", "lo"])
+        XCTAssertEqual(interfaces.map(\.type), ["ether", "ether", "bridge", "loopback"])
+    }
 }