Polish deferred UF2 update flow and docs

OpenPuck/config.cpp

@@ -20,7 +20,8 @@ bool g_debugCdcThisBoot = false;
 
 // persisted one-shot arm, stored in Cfg.rsvd0 (1 = keep CDC for the next boot)
 static uint8_t g_debugCdc = 0;
-// one-shot UF2 arm token, stored in Cfg.rxWin10 (legacy field no longer used)
+// one-shot UF2 arm token, stored in Cfg.rxWin10 (legacy field no longer used). Chosen so typical legacy
+// rxWin10 values (small 10us units) never collide and accidentally arm the updater path.
 static const uint8_t BOOT_UF2_ARM = 0xA5;
 
 int g_mDiv = 64, g_mFric = 94;
@@ -80,9 +81,13 @@ const uint32_t g_pollUs = POLL_US_DEFAULT;
 struct Cfg {
 	uint8_t magic, mode, mDiv, mFric, rsvd0, pollU100, persistMode,
 		bootMode, chordBtn[3], rumbleScale;
-	// rxWin10: one-shot UF2 boot arm token (legacy RF tunable slot, window now fixed). lizKeep: the id9=0 hold
-	// enable (see
-	// haptics.h LIZKEEP_MS). landAll87: the verbatim-0x87-relay experiment toggle (haptics.h g_landAll87).
+	// rxWin10: one-shot UF2 boot arm token (legacy RF tunable slot, window
+	// now fixed).
+	//
+	// lizKeep: id9=0 hold enable (see haptics.h LIZKEEP_MS).
+	//
+	// landAll87: verbatim-0x87-relay experiment toggle
+	// (haptics.h g_landAll87).
 	uint8_t rxWin10, lizKeep, landAll87;
 	TypeCfg type[ET_COUNT]; // per-emulated-type back/qam/abSwap/padHaptics
 }; // rsvd0 = ex-padSmooth, now the one-shot debug-CDC arm
@@ -132,6 +137,7 @@ void loadCfg()
 				g_debugCdc = 0;
 				consume = true;
 			}
+
 			// one-shot UF2 boot (Cfg.rxWin10): honor once, then clear.
 			g_bootUf2ThisBoot = (c.rxWin10 == BOOT_UF2_ARM);
 			if (g_bootUf2ThisBoot) {
@@ -169,7 +175,9 @@ void loadCfg()
 			// verbatim-0x87-relay experiment toggle (0/1; default off)
 			if (c.landAll87 <= 1)
 				g_landAll87 = c.landAll87;
-			// Keep only our explicit arm token; old legacy values never arm UF2 by accident.
+
+			// Keep only our explicit arm token; legacy rxWin10 values
+			// were small 10us units, so they do not collide with 0xA5.
 			if (c.rxWin10 == BOOT_UF2_ARM)
 				g_bootUf2 = BOOT_UF2_ARM;
 			else

docs/index.html

@@ -1085,7 +1085,7 @@ async function startPolling(){
 $("#connectBtn").onclick=connect;
 $("#uf2Pick").onclick=()=>{ $("#uf2File").click(); };
 $("#uf2File").onchange=(e)=>{
-  selectedUf2File = e.target.files && e.target.files[0] ? e.target.files[0] : null;
+  selectedUf2File = e.target.files?.[0] || null;
   updateUf2UI();
   if(selectedUf2File) log("UF2 selected: " + selectedUf2File.name);
 };
@@ -1110,7 +1110,7 @@ $("#uf2Flash").onclick=async()=>{
     log("UF2 copied: " + selectedUf2File.name + " (" + sizeKiB
       + " KiB). Device should reboot automatically within a few seconds.");
   }catch(e){
-    if(e && e.name === "AbortError")
+    if(e.name === "AbortError")
       log("UF2 copy canceled.");
     else
       log("UF2 copy failed: " + e.message);
@@ -1160,7 +1160,7 @@ $("#uf2Next").onclick=async()=>{
   if(!dev){ log("not connected"); return; }
   const on=$("#uf2Next").classList.contains("active");
   await setField(30, on?0:1);
-  log(on?"UF2-on-reboot cleared":"UF2-on-reboot armed — next reboot enters UF2 bootloader");
+  log(on?"UF2-on-reboot cleared":"UF2-on-reboot armed - next reboot enters UF2 bootloader");
 };
 $("#factoryErase").onclick=async()=>{
   if(!dev){ log("not connected"); return; }