Added more safety checks

Implemented more safety/sanity checks:
    *Check for NO$GBA footer when size is normal(i.e. footer replaces end of image, not appended to it).
     Yes, such image works in NO$GBA!
    *Check if battery level is below 50%(2 bars), allow to proceed if charger connected.
Changed order of messages while writing nand to properly ask to not disconnect charger if it is connected.
In same place altered block counter to actually state that it is operation progress.

arm9/source/main.cpp

@@ -247,6 +247,7 @@ void restoreNAND() {
 	}
 
 	//Sanity checks
+
 	//	Size check
 	fseek(f, 0, SEEK_END);
 	size_t dump_size = ftell(f);
@@ -255,7 +256,20 @@ void restoreNAND() {
 		fclose(f);
 		return;
 	}
+	//	NO$GBA footer check in image of normal size
+	//	yes, that works in emulator
+	fseek(f, -64, SEEK_CUR);
+	char ngsign[] = "DSi eMMC CID/CPU\0";
+	char fsign[17];
+	fsign[16] = '\0';
+	fread(fsign, 1, 16, f);
+	if ( !strcmp(ngsign, fsign) ) {
+		iprintf("%s has NO$GBA footer\nthat replaces end of image!\nOperation aborted.", nand_type);
+		fclose(f);
+		return;
+	}	
 	rewind(f);
+
 	//	MBR(decrypted image) check
 	//	Taken from TWLtool (https://github.com/WinterMute/twltool)
 	struct {
@@ -277,6 +291,17 @@ void restoreNAND() {
 		return;
 	}
 	rewind(f);
+
+	//	Battery level/charger check
+	u32 pwrReg = getBatteryLevel();
+	bool isCharging = (pwrReg >> 7) & 1;
+	int batLevel = pwrReg & 0b1111;
+
+	if ( !isCharging && (batLevel < 7) ) {
+		iprintf("Battery level below 50%%(2 bars)\nPlease connect charger.\nOperation aborted.");
+		fclose(f);
+		return;
+	}
 	//Sanity checks end
 
 	iprintf("Sure? NAND restore is DANGEROUS!");
@@ -297,7 +322,13 @@ void restoreNAND() {
 
 	clearStatus();
 
-	iprintf("Reading %s/%s\n\n", dirname, nand_type);
+	if (isCharging) {
+		iprintf("DON'T poweroff console\nor disconnect charger!\n");
+	} else {
+		iprintf("DON'T poweroff console!\n");
+	}
+
+	iprintf("Reading:\n%s/%s\n", dirname, nand_type);
 	size_t i;
 	size_t sectors = 128;
 	size_t blocks = (sizMB * 1024 * 1024) / (sectors * 512);
@@ -315,7 +346,7 @@ void restoreNAND() {
 			break;
 		}
 
-		iprintf("%d/%d DON'T poweroff!\r", i+1, blocks);
+		iprintf("Progress: %d/%d blocks\r", i+1, blocks);
 	}
 	fclose(f);