diff --git a/Common/System/Request.cpp b/Common/System/Request.cpp
index 33ec112840..059f49769b 100644
--- a/Common/System/Request.cpp
+++ b/Common/System/Request.cpp
@@ -95,8 +95,8 @@ void OnScreenDisplay::SetProgressBar(std::string id, std::string &&message, int
 	bool found = false;
 	for (auto &bar : bars_) {
 		if (bar.id == id) {
-			_dbg_assert_(minValue == bar.minValue);
-			_dbg_assert_(maxValue == bar.maxValue);
+			bar.minValue = minValue;
+			bar.maxValue = maxValue;
 			bar.progress = progress;
 			bar.message = message;
 			bar.endTime = now + 60.0;  // Nudge the progress bar to keep it shown.
diff --git a/UI/DevScreens.cpp b/UI/DevScreens.cpp
index 78a82af7f1..277562edad 100644
--- a/UI/DevScreens.cpp
+++ b/UI/DevScreens.cpp
@@ -824,6 +824,10 @@ void SystemInfoScreen::CreateTabs() {
 		g_OSD.SetProgressBar("testprogress", "Test Progress", 1, 100, 100);
 		return UI::EVENT_DONE;
 	});
+	internals->Add(new Choice(si->T("N/A%")))->OnClick.Add([&](UI::EventParams &) {
+		g_OSD.SetProgressBar("testprogress", "Test Progress", 0, 0, 0);
+		return UI::EVENT_DONE;
+	});
 	internals->Add(new Choice(si->T("Clear")))->OnClick.Add([&](UI::EventParams &) {
 		g_OSD.RemoveProgressBar("testprogress", 0.25f);
 		return UI::EVENT_DONE;
diff --git a/UI/OnScreenDisplay.cpp b/UI/OnScreenDisplay.cpp
index c5f5342b85..a8feab680e 100644
--- a/UI/OnScreenDisplay.cpp
+++ b/UI/OnScreenDisplay.cpp
@@ -83,26 +83,40 @@ static void MeasureOSDProgressBar(UIContext &dc, const OnScreenDisplay::Progress
 }
 
 static void RenderOSDProgressBar(UIContext &dc, const OnScreenDisplay::ProgressBar &entry, Bounds bounds, int align, float alpha) {
-	UI::Drawable background = UI::Drawable(colorAlpha(0x806050, alpha));
-	UI::Drawable progressBackground = UI::Drawable(colorAlpha(0xa08070, alpha));
-
 	uint32_t foreGround = whiteAlpha(alpha);
 
 	Bounds shadowBounds = bounds.Expand(10.0f);
 
 	dc.Draw()->DrawImage4Grid(dc.theme->dropShadow4Grid, shadowBounds.x, shadowBounds.y + 4.0f, shadowBounds.x2(), shadowBounds.y2(), alphaMul(0xFF000000, 0.9f * alpha), 1.0f);
 
-	float ratio = (float)(entry.progress - entry.minValue) / (float)entry.maxValue;
+	uint32_t backgroundColor = colorAlpha(0x806050, alpha);
+	uint32_t progressBackgroundColor = colorAlpha(0xa08070, alpha);
 
-	Bounds boundLeft = bounds;
-	Bounds boundRight = bounds;
+	if (entry.maxValue > entry.minValue) {
+		// Normal progress bar
 
-	boundLeft.w *= ratio;
-	boundRight.x += ratio * boundRight.w;
-	boundRight.w *= (1.0f - ratio);
+		UI::Drawable background = UI::Drawable(backgroundColor);
+		UI::Drawable progressBackground = UI::Drawable(progressBackgroundColor);
+
+		float ratio = (float)(entry.progress - entry.minValue) / (float)entry.maxValue;
+
+		Bounds boundLeft = bounds;
+		Bounds boundRight = bounds;
+
+		boundLeft.w *= ratio;
+		boundRight.x += ratio * boundRight.w;
+		boundRight.w *= (1.0f - ratio);
+
+		dc.FillRect(progressBackground, boundLeft);
+		dc.FillRect(background, boundRight);
+	} else {
+		// Indeterminate spinner
+		float alpha = cos(time_now_d() * 5.0) * 0.5f + 0.5f;
+		uint32_t pulse = colorBlend(backgroundColor, progressBackgroundColor, alpha);
+		UI::Drawable background = UI::Drawable(pulse);
+		dc.FillRect(background, bounds);
+	}
 
-	dc.FillRect(progressBackground, boundLeft);
-	dc.FillRect(background, boundRight);
 	dc.SetFontStyle(dc.theme->uiFont);
 
 	dc.DrawTextShadowRect(entry.message.c_str(), bounds, colorAlpha(0xFFFFFFFF, alpha), (align & FLAG_DYNAMIC_ASCII) | ALIGN_CENTER);