diff --git a/src/newgrf_config.cpp b/src/newgrf_config.cpp
--- a/src/newgrf_config.cpp
+++ b/src/newgrf_config.cpp
@@ -307,7 +307,7 @@ size_t GRFGetSizeOfDataSection(FILE *f)
 			/* Valid container version 2, get data section size. */
 			size_t offset = ((size_t)data[13] << 24) | ((size_t)data[12] << 16) | ((size_t)data[11] << 8) | (size_t)data[10];
 			if (offset >= 1 * 1024 * 1024 * 1024) {
-				DEBUG(grf, 0, "Unexpectedly large offset for NewGRF");
+				Debug(grf, 0, "Unexpectedly large offset for NewGRF");
 				/* Having more than 1 GiB of data is very implausible. Mostly because then
 				 * all pools in OpenTTD are flooded already. Or it's just Action C all over.
 				 * In any case, the offsets to graphics will likely not work either. */
@@ -524,7 +524,7 @@ GRFListCompatibility IsGoodGRFConfigList
 			f = FindGRFConfig(c->ident.grfid, FGCM_COMPATIBLE, nullptr, c->version);
 			if (f != nullptr) {
 				md5sumToString(buf, lastof(buf), c->ident.md5sum);
-				DEBUG(grf, 1, "NewGRF %08X (%s) not found; checksum %s. Compatibility mode on", BSWAP32(c->ident.grfid), c->filename, buf);
+				Debug(grf, 1, "NewGRF {:08X} ({}) not found; checksum {}. Compatibility mode on", BSWAP32(c->ident.grfid), c->filename, buf);
 				if (!HasBit(c->flags, GCF_COMPATIBLE)) {
 					/* Preserve original_md5sum after it has been assigned */
 					SetBit(c->flags, GCF_COMPATIBLE);
@@ -538,13 +538,13 @@ GRFListCompatibility IsGoodGRFConfigList
 
 			/* No compatible grf was found, mark it as disabled */
 			md5sumToString(buf, lastof(buf), c->ident.md5sum);
-			DEBUG(grf, 0, "NewGRF %08X (%s) not found; checksum %s", BSWAP32(c->ident.grfid), c->filename, buf);
+			Debug(grf, 0, "NewGRF {:08X} ({}) not found; checksum {}", BSWAP32(c->ident.grfid), c->filename, buf);
 
 			c->status = GCS_NOT_FOUND;
 			res = GLC_NOT_FOUND;
 		} else {
 compatible_grf:
-			DEBUG(grf, 1, "Loading GRF %08X from %s", BSWAP32(f->ident.grfid), f->filename);
+			Debug(grf, 1, "Loading GRF {:08X} from {}", BSWAP32(f->ident.grfid), f->filename);
 			/* The filename could be the filename as in the savegame. As we need
 			 * to load the GRF here, we need the correct filename, so overwrite that
 			 * in any case and set the name and info when it is not set already.
@@ -673,10 +673,10 @@ void DoScanNewGRFFiles(NewGRFScanCallbac
 	ClearGRFConfigList(&_all_grfs);
 	TarScanner::DoScan(TarScanner::NEWGRF);
 
-	DEBUG(grf, 1, "Scanning for NewGRFs");
+	Debug(grf, 1, "Scanning for NewGRFs");
 	uint num = GRFFileScanner::DoScan();
 
-	DEBUG(grf, 1, "Scan complete, found %d files", num);
+	Debug(grf, 1, "Scan complete, found {} files", num);
 	if (num != 0 && _all_grfs != nullptr) {
 		/* Sort the linked list using quicksort.
 		 * For that we first have to make an array, then sort and