diff --git a/auth-proxy/src/index.ts b/auth-proxy/src/index.ts
index a87e380..d2faa4b 100644
--- a/auth-proxy/src/index.ts
+++ b/auth-proxy/src/index.ts
@@ -109,8 +109,14 @@ app.post<{
   Body: { cashaddr: string; state?: string; redirect_uri?: string };
 }>("/challenge", async (req, reply) => {
   const { cashaddr, state, redirect_uri } = req.body ?? {};
-  if (!cashaddr || !cashaddr.startsWith("bitcoincash:")) {
-    return reply.code(400).send({ error: "cashaddr must start with bitcoincash:" });
+  // Accept any CashAddr prefix the chain actually uses:
+  //   bitcoincash:  (mainnet)
+  //   bchtest:      (chipnet / testnet — what Silent Mode's whole stack runs on today)
+  //   bchreg:       (regtest)
+  if (!cashaddr || !/^(bitcoincash|bchtest|bchreg):/.test(cashaddr)) {
+    return reply.code(400).send({
+      error: "cashaddr must start with bitcoincash:, bchtest: or bchreg:",
+    });
   }
   const rec = createChallenge(cashaddr, state, redirect_uri);
   const message = buildChallenge({
@@ -123,10 +129,14 @@ app.post<{
 });
 
 // --- Signature verification & OAuth code mint ---
+// `state` in the body is a fallback so scripted callers who bypass /challenge's
+// state-passing (or use their own OAuth kickoff wrapper) can still get RFC 6749
+// §4.1.2 compliant callbacks. If state was stored via /challenge it's used
+// automatically; explicit body override wins if both are present.
 app.post<{
-  Body: { nonce: string; signature: string };
+  Body: { nonce: string; signature: string; state?: string; redirect_uri?: string };
 }>("/verify", async (req, reply) => {
-  const { nonce, signature } = req.body ?? {};
+  const { nonce, signature, state: stateOverride, redirect_uri: redirectOverride } = req.body ?? {};
   if (!nonce || !signature) {
     return reply.code(400).send({ error: "nonce and signature required" });
   }
@@ -142,11 +152,12 @@ app.post<{
   const recovered = verifyBchSignedMessage(rec.cashaddr, message, signature);
   if (!recovered) return reply.code(401).send({ error: "signature mismatch" });
 
-  const redirectUri = rec.redirectUri ?? FORGEJO_REDIRECT_URI;
+  const redirectUri = redirectOverride ?? rec.redirectUri ?? FORGEJO_REDIRECT_URI;
   const code = mintAuthCode(recovered, CLIENT_ID, redirectUri);
   const url = new URL(redirectUri);
   url.searchParams.set("code", code);
-  if (rec.clientState) url.searchParams.set("state", rec.clientState);
+  const stateToEcho = stateOverride ?? rec.clientState;
+  if (stateToEcho) url.searchParams.set("state", stateToEcho);
   return { redirect: url.toString() };
 });
 
diff --git a/auth-proxy/src/verify.ts b/auth-proxy/src/verify.ts
index a55d384..76e266b 100644
--- a/auth-proxy/src/verify.ts
+++ b/auth-proxy/src/verify.ts
@@ -62,13 +62,28 @@ function magicHash(message: string): Uint8Array {
 /**
  * Verify a base64 recoverable-ECDSA signature against a message and cashaddr.
  * Returns the recovered cashaddr on success, or null on any mismatch.
+ *
+ * The prefix is auto-detected from the claimed cashaddr, so both
+ *   bitcoincash:qq... (mainnet)
+ *   bchtest:qq...    (chipnet / testnet)
+ *   bchreg:qq...     (regtest)
+ * work with identical key material. This matters because chipnet wallets
+ * (which the whole Silent Mode stack runs on today) sign the same message
+ * with the same key, but display their address with the bchtest: prefix.
  */
+const KNOWN_PREFIXES = ["bitcoincash", "bchtest", "bchreg"] as const;
+type Prefix = (typeof KNOWN_PREFIXES)[number];
+
 export function verifyBchSignedMessage(
   claimedCashaddr: string,
   message: string,
   signatureBase64: string,
-  prefix: "bitcoincash" | "bchtest" = "bitcoincash",
 ): string | null {
+  const prefixMatch = claimedCashaddr.match(/^([a-z]+):/);
+  if (!prefixMatch) return null;
+  const prefix = prefixMatch[1] as Prefix;
+  if (!KNOWN_PREFIXES.includes(prefix)) return null;
+
   const sig = base64ToBin(signatureBase64);
   if (typeof sig === "string" || sig.length !== 65) return null;