diff --git a/CHANGELOG.md b/CHANGELOG.md
index 4d4de397..31dc0cce 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -23,6 +23,9 @@ had changed in them - which is the gap this file exists to close.
 
 ### Added
 
+- **Two more boards emulate.** Heltec E290 and Heltec Wireless Tracker V2
+  passed the board probe against v1.17.1 (build, boot, radio, transmit,
+  receive and flood), so they are offered for emulation.
 - **Script input at an instant of simulated time.** `console.type`,
   `console.cli` and the `companion.*` verbs that write to a node take `at_ms`:
   the call is held and runs when the run reaches that instant, so a script
@@ -52,6 +55,10 @@ had changed in them - which is the gap this file exists to close.
 
 ### Fixed
 
+- **A board probe says when GitHub's rate limit stopped it.** Out of
+  unauthenticated API allowance, it reported that the firmware catalogue
+  could not be reached; it now says the allowance is used up, until when, and
+  that `GITHUB_TOKEN` raises it.
 - **Emulated nRF52 boards keep what they store.** The factory registers never
   said how big the flash was, so the SoftDevice refused every erase and write
   with `NRF_ERROR_FORBIDDEN`: the filesystem could not be formatted, and
diff --git a/internal/firmware/board/board_heltec_e290.go b/internal/firmware/board/board_heltec_e290.go
index 04e3f13f..b7f1fd17 100644
--- a/internal/firmware/board/board_heltec_e290.go
+++ b/internal/firmware/board/board_heltec_e290.go
@@ -20,6 +20,9 @@ var heltecE290Board = Board{
 		// Serial is the USB port on this board: its MeshCore variant is
 		// built with ARDUINO_USB_CDC_ON_BOOT.
 		ConsoleOnUSB: true,
+		// Watched booting, transmitting and hearing a neighbour by the board
+		// probe against v1.17.1 (#603).
+		Verified: true,
 	},
 	Hardware: &Panel{
 		Parts: []Part{
diff --git a/internal/firmware/board/board_heltec_tracker_v2.go b/internal/firmware/board/board_heltec_tracker_v2.go
index 36169293..eaee9c4d 100644
--- a/internal/firmware/board/board_heltec_tracker_v2.go
+++ b/internal/firmware/board/board_heltec_tracker_v2.go
@@ -17,6 +17,9 @@ var heltecTrackerV2Board = Board{
 		// Serial is the USB port on this board: its MeshCore variant is
 		// built with ARDUINO_USB_CDC_ON_BOOT.
 		ConsoleOnUSB: true,
+		// Watched booting, transmitting and hearing a neighbour by the board
+		// probe against v1.17.1 (#603).
+		Verified: true,
 	},
 	Hardware: &Panel{
 		Parts: []Part{
diff --git a/internal/firmware/board/boards.go b/internal/firmware/board/boards.go
index 05c7a637..fd2edf17 100644
--- a/internal/firmware/board/boards.go
+++ b/internal/firmware/board/boards.go
@@ -366,6 +366,11 @@ var EmulationVerified = []string{
 	"Xiao_S3",
 	"Xiao_S3_WIO",
 	"RAK_3112",
+	// Probed for #603 against v1.17.1: build, boot, radio, tx, rx and flood
+	// all passed. The E290's e-paper panel is still not drawn - the board
+	// runs, its display is the gap.
+	"Heltec_E290",
+	"heltec_tracker_v2",
 }
 
 // EmulationSupported reports whether a board can be run under emulation today.
diff --git a/internal/firmware/emulated/board_catalogue.go b/internal/firmware/emulated/board_catalogue.go
index b0eec904..e569f7d5 100644
--- a/internal/firmware/emulated/board_catalogue.go
+++ b/internal/firmware/emulated/board_catalogue.go
@@ -12,7 +12,9 @@ import (
 	"path/filepath"
 	"regexp"
 	"sort"
+	"strconv"
 	"strings"
+	"time"
 
 	"github.com/MeshBench/meshbench/internal/firmware"
 )
@@ -386,11 +388,33 @@ func (c *BoardCatalogue) get(ctx context.Context, url, accept string) (io.ReadCl
 	}
 	if resp.StatusCode != http.StatusOK {
 		_ = resp.Body.Close()
+		if limited := rateLimited(resp); limited != "" {
+			return nil, fmt.Errorf("%s returned %s: %s", url, resp.Status, limited)
+		}
 		return nil, fmt.Errorf("%s returned %s", url, resp.Status)
 	}
 	return resp.Body, nil
 }
 
+// rateLimited says so when GitHub refused because this address has used its
+// allowance, which reads otherwise as the catalogue being unreachable. Sixty
+// unauthenticated requests an hour is a handful of board probes.
+func rateLimited(resp *http.Response) string {
+	if resp.StatusCode != http.StatusForbidden && resp.StatusCode != http.StatusTooManyRequests {
+		return ""
+	}
+	if resp.Header.Get("X-RateLimit-Remaining") != "0" {
+		return ""
+	}
+	when := ""
+	if reset, err := strconv.ParseInt(resp.Header.Get("X-RateLimit-Reset"), 10, 64); err == nil {
+		when = " until " + time.Unix(reset, 0).Format("15:04")
+	}
+	return "GitHub's API allowance for this address is used up" + when +
+		"; set GITHUB_TOKEN (export GITHUB_TOKEN=$(gh auth token)) to raise it. " +
+		"Already-downloaded images keep working without it"
+}
+
 // countingReader reports as it goes, throttled to whole percent so a slow
 // link does not spend its time posting verbs instead of reading bytes.
 type countingReader struct {
diff --git a/internal/firmware/emulated/ratelimit_test.go b/internal/firmware/emulated/ratelimit_test.go
new file mode 100644
index 00000000..6701f869
--- /dev/null
+++ b/internal/firmware/emulated/ratelimit_test.go
@@ -0,0 +1,23 @@
+package emulated
+
+import (
+	"net/http"
+	"strings"
+	"testing"
+)
+
+// A refusal because this address has used its API allowance says so, rather
+// than reading as a catalogue that could not be reached (#603: five board
+// probes in a row failed that way).
+func TestARateLimitIsSaid(t *testing.T) {
+	resp := &http.Response{StatusCode: http.StatusForbidden, Header: http.Header{}}
+	resp.Header.Set("X-RateLimit-Remaining", "0")
+	resp.Header.Set("X-RateLimit-Reset", "1792894182")
+	if got := rateLimited(resp); !strings.Contains(got, "GITHUB_TOKEN") {
+		t.Errorf("a rate limit read as %q", got)
+	}
+	resp.Header.Set("X-RateLimit-Remaining", "12")
+	if got := rateLimited(resp); got != "" {
+		t.Errorf("a 403 with allowance left read as a rate limit: %q", got)
+	}
+}