--- mformat.c.orig	2013-01-08 23:14:21.000000000 +0100
+++ mformat.c	2018-08-11 15:26:57.772597760 +0200
@@ -721,6 +721,7 @@ static void usage(int ret)
 #ifdef OS_linux
 static int get_block_geom(int fd, struct device *dev, char *errmsg) {
 	struct hd_geometry geom;
+	int sec_size;
 	long size;
 	int heads=dev->heads;
 	int sectors=dev->sectors;
@@ -738,6 +739,16 @@ static int get_block_geom(int fd, struct
 		return -1;
 	}
 
+	if (ioctl(fd, BLKSSZGET, &sec_size) != 0 || sec_size <= 0) {
+		sprintf(errmsg, "Could not get block size of device (%s)",
+			strerror(errno));
+		return -1;
+	}
+
+	dev->ssize = 0;
+	while (dev->ssize < 0x7F && (128 << dev->ssize) < sec_size)
+		dev->ssize++;
+
 	if(!heads)
 		heads = geom.heads;
 	if(!sectors)
@@ -763,6 +774,93 @@ static int get_block_geom(int fd, struct
 }
 #endif
 
+static int get_lba_geom(Stream_t *Direct, unsigned long tot_sectors, struct device *dev, char *errmsg) {
+	int sect_per_track;
+	unsigned long tracks;
+
+	/* if one value is already specified we do not want to overwrite it */
+	if (dev->heads || dev->sectors || dev->tracks) {
+		sprintf(errmsg, "Number of heads or sectors or tracks was already specified");
+		return -1;
+	}
+
+	if (!tot_sectors) {
+#ifdef OS_linux
+		int fd;
+		int sec_size;
+		long size;
+		struct MT_STAT stbuf;
+
+		fd = get_fd(Direct);
+		if (MT_FSTAT(fd, &stbuf) < 0) {
+			sprintf(errmsg, "Could not stat file (%s)", strerror(errno));
+			return -1;
+		}
+
+		if (S_ISBLK(stbuf.st_mode)) {
+			if (ioctl(fd, BLKGETSIZE, &size) != 0) {
+				sprintf(errmsg, "Could not get size of device (%s)",
+					strerror(errno));
+				return -1;
+			}
+			if (ioctl(fd, BLKSSZGET, &sec_size) != 0 || sec_size <= 0) {
+				sprintf(errmsg, "Could not get block size of device (%s)",
+					strerror(errno));
+				return -1;
+			}
+			if (!(dev->ssize & 0x80)) {
+				dev->ssize = 0;
+				while (dev->ssize < 0x7F && (128 << dev->ssize) < sec_size)
+				dev->ssize++;
+			}
+			if ((dev->ssize & 0x7f) > 2)
+				tot_sectors = size >> ((dev->ssize & 0x7f) - 2);
+			else
+				tot_sectors = size << (2 - (dev->ssize & 0x7f));
+		} else if (S_ISREG(stbuf.st_mode)) {
+			tot_sectors = stbuf.st_size >> ((dev->ssize & 0x7f) + 7);
+		} else {
+			sprintf(errmsg, "Could not get size of device (%s)",
+				"No method available");
+			return -1;
+		}
+#else
+		mt_size_t size;
+		GET_DATA(Direct, 0, &size, 0, 0);
+		if (size == 0) {
+			sprintf(errmsg, "Could not get size of device (%s)",
+				"No method available");
+			return -1;
+		}
+		tot_sectors = size >> ((dev->ssize & 0x7f) + 7);
+#endif
+	}
+
+	dev->sectors = 63;
+
+	if (tot_sectors < 16*63*1024)
+		dev->heads = 16;
+	else if (tot_sectors < 32*63*1024)
+		dev->heads = 32;
+	else if (tot_sectors < 64*63*1024)
+		dev->heads = 64;
+	else if (tot_sectors < 128*63*1024)
+		dev->heads = 128;
+	else
+		dev->heads = 255;
+
+	sect_per_track = dev->heads * dev->sectors;
+	tracks = (tot_sectors + dev->hidden % sect_per_track) / sect_per_track;
+	if (tracks > 0xFFFFFFFF) {
+		sprintf(errmsg, "Device is too big, it has too many tracks");
+		return -1;
+	}
+
+	dev->tracks = tracks;
+
+	return 0;
+}
+
 void mformat(int argc, char **argv, int dummy)
 {
 	int r; /* generic return value */
@@ -1117,19 +1215,21 @@ void mformat(int argc, char **argv, int
 
 			if (S_ISBLK(stbuf.st_mode) &&
 			    get_block_geom(fd, &used_dev, errmsg) < 0)
-				continue;
+				fprintf(stderr, "%s: %s\n", argv[0], errmsg);
 		}
 #endif
 
-		/* no way to find out geometry */
 		if ((!used_dev.tracks && !tot_sectors) ||
 		     !used_dev.heads || !used_dev.sectors){
-			sprintf(errmsg,
-				"Unknown geometry "
-				"(You must tell the complete geometry "
-				"of the disk, \neither in /etc/mtools.conf or "
-				"on the command line) ");
-			continue;
+			printf("%s: "
+				"Complete geometry of the disk was not specified, \n"
+				"neither in /etc/mtools.conf nor on the command line. \n"
+				"Using LBA Assist Translation for calculating CHS geometry "
+				"of the disk.\n", argv[0]);
+			if (get_lba_geom(Fs.Direct, tot_sectors, &used_dev, errmsg) < 0)
+				continue;
+			printf("sector size: %u, sectors: %u, heads: %u, tracks: %u\n",
+				128 << (used_dev.ssize & 0x7f), used_dev.sectors, used_dev.heads, used_dev.tracks);
 		}
 
 #if 0
@@ -1143,6 +1243,8 @@ void mformat(int argc, char **argv, int
 		Fs.sector_size = 512;
 		if( !(used_dev.use_2m & 0x7f)) {
 			Fs.sector_size = 128 << (used_dev.ssize & 0x7f);
+			if (Fs.sector_size > 4096)
+				Fs.sector_size = 4096;
 		}
 
 		SET_INT(Fs.sector_size, msize);