diff --git a/src/gdbserver.rs b/src/gdbserver.rs
index b25767a..ce49814 100644
--- a/src/gdbserver.rs
+++ b/src/gdbserver.rs
@@ -239,7 +239,7 @@ impl GdbConnection {
                 self.response()
             }
         } else if req.match_str("vCont?") {
-            self.response().write_str("vCont;c;")
+            self.response().write_str("vCont;c;s;")
         } else if req.match_str("qC") {
             // The v810 has no threads, so report that the "current thread" is 1.
             self.response().write_str("QCp1.t1")
@@ -258,7 +258,7 @@ impl GdbConnection {
             self.stop_reason = None;
             // Don't send a response until we hit a breakpoint or get interrupted
             return Ok(None);
-        } else if req.match_str("s") {
+        } else if req.match_some_str(["s", "vCont;s:"]).is_some() {
             self.client
                 .send_command(EmulatorCommand::DebugStep(self.sim_id));
             self.stop_reason = None;
@@ -280,13 +280,25 @@ impl GdbConnection {
             }
         } else if let Some(op) = req.match_some_str(["m", "x"]) {
             let mut read_memory = || {
-                let start = req.match_hex::<u64>()? as u32;
+                let start = req.match_hex::<u64>()?;
                 if !req.match_str(",") {
                     return None;
                 };
                 let length = req.match_hex::<usize>()?;
+
                 let mut buf = self.memory_buf.take().unwrap_or_default();
                 buf.clear();
+
+                // The v810 has a 32-bit address space.
+                // Addresses wrap within that space, but we don't need to implement that for 64-bit addresses.
+                // Just refuse to return any info for addresses above 0xffffffff.
+                let Ok(start) = u32::try_from(start) else {
+                    return Some(buf);
+                };
+                let length = length.min((u32::MAX - start) as usize + 1);
+                if length == 0 {
+                    return Some(buf);
+                }
                 let (tx, rx) = ::oneshot::channel();
                 self.client.send_command(EmulatorCommand::ReadMemory(
                     self.sim_id,
@@ -299,7 +311,9 @@ impl GdbConnection {
             };
             if let Some(memory) = read_memory() {
                 let mut res = self.response();
-                if op == "m" {
+                if memory.is_empty() {
+                    res = res.write_str("OK");
+                } else if op == "m" {
                     // send the hex-encoded byte stream
                     for byte in &memory {
                         res = res.write_hex(*byte);