diff --git a/src/chipset/scat.c b/src/chipset/scat.c
index fce0e772b..79f18d396 100644
--- a/src/chipset/scat.c
+++ b/src/chipset/scat.c
@@ -1056,17 +1056,14 @@ scat_out(uint16_t port, uint8_t val, void *priv)
 				break;
 
 			case SCAT_EMS_CONTROL:
+				io_removehandler(0x0208, 0x0003, scat_in, NULL, NULL, scat_out, NULL, NULL, dev);
+				io_removehandler(0x0218, 0x0003, scat_in, NULL, NULL, scat_out, NULL, NULL, dev);
+
 				if (val & 0x40) {
-					if (val & 1) {
+					if (val & 1)
 						io_sethandler(0x0218, 3, scat_in, NULL, NULL, scat_out, NULL, NULL, dev);
-						io_removehandler(0x0208, 3, scat_in, NULL, NULL, scat_out, NULL, NULL, dev);
-					} else {
+					else
 						io_sethandler(0x0208, 3, scat_in, NULL, NULL, scat_out, NULL, NULL, dev);
-						io_removehandler(0x0218, 3, scat_in, NULL, NULL, scat_out, NULL, NULL, dev);
-					}
-				} else {
-					io_removehandler(0x0208, 0x0003, scat_in, NULL, NULL, scat_out, NULL, NULL, dev);
-					io_removehandler(0x0218, 0x0003, scat_in, NULL, NULL, scat_out, NULL, NULL, dev);
 				}
 				set_global_EMS_state(dev, val & 0x80);
 				reg_valid = 1;
diff --git a/src/disk/hdc_st506_xt.c b/src/disk/hdc_st506_xt.c
index 5831fee88..a980ec6e8 100644
--- a/src/disk/hdc_st506_xt.c
+++ b/src/disk/hdc_st506_xt.c
@@ -1333,7 +1333,8 @@ loadrom(hdc_t *dev, const wchar_t *fn)
     /* Load the ROM data. */
     dev->bios_rom.rom = (uint8_t *)malloc(size);
     memset(dev->bios_rom.rom, 0xff, size);
-    (void)fread(dev->bios_rom.rom, size, 1, fp);
+    if (fread(dev->bios_rom.rom, 1, size, fp) != size)
+	fatal("ST-506 XT loadrom(): Error reading data\n");
     (void)fclose(fp);
 
     /* Set up an address mask for this memory. */
diff --git a/src/disk/hdd_image.c b/src/disk/hdd_image.c
index 5a84116eb..26c312824 100644
--- a/src/disk/hdd_image.c
+++ b/src/disk/hdd_image.c
@@ -641,13 +641,19 @@ hdd_image_load(int id)
 	}
     } else {
 	if (image_is_hdi(fn)) {
-		fseeko64(hdd_images[id].file, 0x8, SEEK_SET);
-		fread(&(hdd_images[id].base), 1, 4, hdd_images[id].file);
-		fseeko64(hdd_images[id].file, 0xC, SEEK_SET);
+		if (fseeko64(hdd_images[id].file, 0x8, SEEK_SET) == -1)
+			fatal("hdd_image_load(): HDI: Error seeking to offset 0x8\n");
+		if (fread(&(hdd_images[id].base), 1, 4, hdd_images[id].file) != 4)
+			fatal("hdd_image_load(): HDI: Error reading base offset\n");
+		if (fseeko64(hdd_images[id].file, 0xC, SEEK_SET) == -1)
+			fatal("hdd_image_load(): HDI: Error seeking to offest 0xC\n");
 		full_size = 0LL;
-		fread(&full_size, 1, 4, hdd_images[id].file);
-		fseeko64(hdd_images[id].file, 0x10, SEEK_SET);
-		fread(&sector_size, 1, 4, hdd_images[id].file);
+		if (fread(&full_size, 1, 4, hdd_images[id].file) != 4)
+			fatal("hdd_image_load(): HDI: Error reading full size\n");
+		if (fseeko64(hdd_images[id].file, 0x10, SEEK_SET) == -1)
+			fatal("hdd_image_load(): HDI: Error seeking to offset 0x10\n");
+		if (fread(&sector_size, 1, 4, hdd_images[id].file) != 4)
+			fatal("hdd_image_load(): HDI: Error reading sector size\n");
 		if (sector_size != 512) {
 			/* Sector size is not 512 */
 			hdd_image_log("HDI: Sector size is not 512\n");
@@ -656,19 +662,26 @@ hdd_image_load(int id)
 			memset(hdd[id].fn, 0, sizeof(hdd[id].fn));
 			return 0;
 		}
-		fread(&spt, 1, 4, hdd_images[id].file);
-		fread(&hpc, 1, 4, hdd_images[id].file);
-		fread(&tracks, 1, 4, hdd_images[id].file);
+		if (fread(&spt, 1, 4, hdd_images[id].file) != 4)
+			fatal("hdd_image_load(): HDI: Error reading sectors per track\n");
+		if (fread(&hpc, 1, 4, hdd_images[id].file) != 4)
+			fatal("hdd_image_load(): HDI: Error reading heads per cylinder\n");
+		if (fread(&tracks, 1, 4, hdd_images[id].file) != 4)
+			fatal("hdd_image_load(): HDI: Error reading number of tracks\n");
 		hdd[id].spt = spt;
 		hdd[id].hpc = hpc;
 		hdd[id].tracks = tracks;
 		hdd_images[id].type = 1;
 	} else if (is_hdx[1]) {
 		hdd_images[id].base = 0x28;
-		fseeko64(hdd_images[id].file, 8, SEEK_SET);
-		fread(&full_size, 1, 8, hdd_images[id].file);
-		fseeko64(hdd_images[id].file, 0x10, SEEK_SET);
-		fread(&sector_size, 1, 4, hdd_images[id].file);
+		if (fseeko64(hdd_images[id].file, 8, SEEK_SET) == -1)
+			fatal("hdd_image_load(): HDX: Error seeking to offset 0x8\n");
+		if (fread(&full_size, 1, 8, hdd_images[id].file) != 8)
+			fatal("hdd_image_load(): HDX: Error reading full size\n");
+		if (fseeko64(hdd_images[id].file, 0x10, SEEK_SET) == -1)
+			fatal("hdd_image_load(): HDX: Error seeking to offset 0x10\n");
+		if (fread(&sector_size, 1, 4, hdd_images[id].file) != 4)
+			fatal("hdd_image_load(): HDX: Error reading sector size\n");
 		if (sector_size != 512) {
 			/* Sector size is not 512 */
 			hdd_image_log("HDX: Sector size is not 512\n");
@@ -677,16 +690,21 @@ hdd_image_load(int id)
 			memset(hdd[id].fn, 0, sizeof(hdd[id].fn));
 			return 0;
 		}
-		fread(&spt, 1, 4, hdd_images[id].file);
-		fread(&hpc, 1, 4, hdd_images[id].file);
-		fread(&tracks, 1, 4, hdd_images[id].file);
+		if (fread(&spt, 1, 4, hdd_images[id].file) != 4)
+			fatal("hdd_image_load(): HDI: Error reading sectors per track\n");
+		if (fread(&hpc, 1, 4, hdd_images[id].file) != 4)
+			fatal("hdd_image_load(): HDI: Error reading heads per cylinder\n");
+		if (fread(&tracks, 1, 4, hdd_images[id].file) != 4)
+			fatal("hdd_image_load(): HDX: Error reading number of tracks\n");
 		hdd[id].spt = spt;
 		hdd[id].hpc = hpc;
 		hdd[id].tracks = tracks;
 		hdd_images[id].type = 2;
 	} else if (is_vhd[1]) {
-		fseeko64(hdd_images[id].file, -512, SEEK_END);
-		fread(empty_sector, 1, 512, hdd_images[id].file);
+		if (fseeko64(hdd_images[id].file, -512, SEEK_END) == -1)
+			fatal("hdd_image_load(): VHD: Error seeking to 512 bytes before the end of file\n");
+		if (fread(empty_sector, 1, 512, hdd_images[id].file) != 512)
+			fatal("hdd_image_load(): HDX: Error reading the footer\n");
 		new_vhd_footer(&vft);
 		vhd_footer_from_bytes(vft, (uint8_t *) empty_sector);
 		if (vft->type != 2) {
@@ -720,7 +738,8 @@ hdd_image_load(int id)
 	}
     }
 
-    fseeko64(hdd_images[id].file, 0, SEEK_END);
+    if (fseeko64(hdd_images[id].file, 0, SEEK_END) == -1)
+	fatal("hdd_image_load(): Error seeking to the end of file\n");
     s = ftello64(hdd_images[id].file);
     if (s < (full_size + hdd_images[id].base))
 	ret = prepare_new_hard_disk(id, full_size);
@@ -731,7 +750,8 @@ hdd_image_load(int id)
     }
 
     if (is_vhd[0]) {
-	fseeko64(hdd_images[id].file, 0, SEEK_END);
+	if (fseeko64(hdd_images[id].file, 0, SEEK_END) == -1)
+		fatal("hdd_image_load(): VHD: Error seeking to the end of file\n");
 	s = ftello64(hdd_images[id].file);
 	if (s == (full_size + hdd_images[id].base)) {
 		/* VHD image. */
diff --git a/src/disk/zip.c b/src/disk/zip.c
index 85f4e677f..9185aafae 100644
--- a/src/disk/zip.c
+++ b/src/disk/zip.c
@@ -527,7 +527,8 @@ zip_load(zip_t *dev, wchar_t *fn)
 
     dev->drv->medium_size = size >> 9;
 
-    fseek(dev->drv->f, dev->drv->base, SEEK_SET);
+    if (fseek(dev->drv->f, dev->drv->base, SEEK_SET) == -1)
+	fatal("zip_load(): Error seeking to the beginning of the file\n");
 
     memcpy(dev->drv->image_path, fn, sizeof(dev->drv->image_path));
 
@@ -1180,10 +1181,13 @@ zip_blocks(zip_t *dev, int32_t *len, int first_batch, int out)
 	if (feof(dev->drv->f))
 		break;
 
-	if (out)
-		fwrite(dev->buffer + (i << 9), 1, 512, dev->drv->f);
-	else
-		fread(dev->buffer + (i << 9), 1, 512, dev->drv->f);
+	if (out) {
+		if (fwrite(dev->buffer + (i << 9), 1, 512, dev->drv->f) != 512)
+			fatal("zip_blocks(): Error writing data\n");
+	} else {
+		if (fread(dev->buffer + (i << 9), 1, 512, dev->drv->f) != 512)
+			fatal("zip_blocks(): Error reading data\n");
+	}
     }
 
     zip_log("%s %i bytes of blocks...\n", out ? "Written" : "Read", *len);
@@ -1444,6 +1448,7 @@ zip_command(scsi_common_t *sc, uint8_t *cdb)
 			zip_invalid_field(dev);
 			return;
 		}
+		/*FALLTHROUGH*/
 	case GPCMD_SCSI_RESERVE:
 	case GPCMD_SCSI_RELEASE:
 	case GPCMD_TEST_UNIT_READY:
diff --git a/src/floppy/fdd_86f.c b/src/floppy/fdd_86f.c
index 797d6bf80..70540105b 100644
--- a/src/floppy/fdd_86f.c
+++ b/src/floppy/fdd_86f.c
@@ -3161,7 +3161,7 @@ d86f_writeback(int drive)
 {
     d86f_t *dev = d86f[drive];
     uint8_t header[32];
-    int header_size;
+    int header_size, size;
 #ifdef D86F_COMPRESS
     uint32_t len;
     int ret = 0;
@@ -3172,11 +3172,16 @@ d86f_writeback(int drive)
     if (! dev->f) return;
 
     /* First write the track offsets table. */
-    fseek(dev->f, 0, SEEK_SET);
-    fread(header, 1, header_size, dev->f);
+    if (fseek(dev->f, 0, SEEK_SET) == -1)
+		fatal("86F write_back(): Error seeking to the beginning of the file\n");
+    if (fread(header, 1, header_size, dev->f) != header_size)
+		fatal("86F write_back(): Error reading header size\n");
 
-    fseek(dev->f, 8, SEEK_SET);
-    fwrite(dev->track_offset, 1, d86f_get_track_table_size(drive), dev->f);
+    if (fseek(dev->f, 8, SEEK_SET) == -1)
+		fatal("86F write_back(): Error seeking\n");
+    size = d86f_get_track_table_size(drive);
+    if (fwrite(dev->track_offset, 1, size, dev->f) != size)
+		fatal("86F write_back(): Error writing data\n");
 
     d86f_write_tracks(drive, &dev->f, NULL);
 
@@ -3586,7 +3591,9 @@ d86f_load(int drive, wchar_t *fn)
 	return;
     }
 
-    fread(&(dev->version), 2, 1, dev->f);
+    if (fread(&(dev->version), 1, 2, dev->f) != 2)
+	fatal("d86f_load(): Error reading format version\n");
+
     if (dev->version != D86FVER) {
 	/* File is not of a recognized format version, abort. */
 	if (dev->version == 0x0063) {
diff --git a/src/floppy/fdd_imd.c b/src/floppy/fdd_imd.c
index 421e339cf..c892e24c5 100644
--- a/src/floppy/fdd_imd.c
+++ b/src/floppy/fdd_imd.c
@@ -638,8 +638,10 @@ imd_load(int drive, wchar_t *fn)
 	writeprot[drive] = 1;
     fwriteprot[drive] = writeprot[drive];
 
-    fseek(dev->f, 0, SEEK_SET);
-    fread(&magic, 1, 4, dev->f);
+    if (fseek(dev->f, 0, SEEK_SET) == -1)
+	fatal("imd_load(): Error seeking to the beginning of the file\n");
+    if (fread(&magic, 1, 4, dev->f) != 4)
+	fatal("imd_load(): Error reading the magic number\n");
     if (magic != 0x20444D49) {
 	imd_log("IMD: Not a valid ImageDisk image\n");
 	fclose(dev->f);
@@ -649,11 +651,14 @@ imd_load(int drive, wchar_t *fn)
     } else
 	imd_log("IMD: Valid ImageDisk image\n");
 
-    fseek(dev->f, 0, SEEK_END);
+    if (fseek(dev->f, 0, SEEK_END) == -1)
+	fatal("imd_load(): Error seeking to the end of the file\n");
     fsize = ftell(dev->f);
-    fseek(dev->f, 0, SEEK_SET);
+    if (fseek(dev->f, 0, SEEK_SET) == -1)
+	fatal("imd_load(): Error seeking to the beginning of the file again\n");
     dev->buffer = malloc(fsize);
-    fread(dev->buffer, 1, fsize, dev->f);
+    if (fread(dev->buffer, 1, fsize, dev->f) != fsize)
+	fatal("imd_load(): Error reading data\n");
     buffer = dev->buffer;
 
     buffer2 = strchr(buffer, 0x1A);
diff --git a/src/floppy/fdd_mfm.c b/src/floppy/fdd_mfm.c
index c2062baad..6da06f48d 100644
--- a/src/floppy/fdd_mfm.c
+++ b/src/floppy/fdd_mfm.c
@@ -401,7 +401,7 @@ mfm_load(int drive, wchar_t *fn)
 {
     mfm_t *dev;
     double dbr;
-    int i;
+    int i, size;
 
     writeprot[drive] = fwriteprot[drive] = 1;
 
@@ -419,16 +419,22 @@ mfm_load(int drive, wchar_t *fn)
     d86f_unregister(drive);
 
     /* Read the header. */
-    fread(&dev->hdr, 1, sizeof(mfm_header_t), dev->f);
+    size = sizeof(mfm_header_t);
+    if (fread(&dev->hdr, 1, size, dev->f) != size)
+	fatal("mfm_load(): Error reading header\n");
 
     /* Calculate tracks * sides, allocate the tracks array, and read it. */
     dev->total_tracks = dev->hdr.tracks_no * dev->hdr.sides_no;
     if (dev->hdr.if_type & 0x80) {
 	dev->adv_tracks = (mfm_adv_track_t *) malloc(dev->total_tracks * sizeof(mfm_adv_track_t));
-	fread(dev->adv_tracks, 1, dev->total_tracks * sizeof(mfm_adv_track_t), dev->f);
+	size = dev->total_tracks * sizeof(mfm_adv_track_t);
+	if (fread(dev->adv_tracks, 1, size, dev->f) != size)
+		fatal("mfm_load(): Error reading advanced tracks\n");
     } else {
 	dev->tracks = (mfm_track_t *) malloc(dev->total_tracks * sizeof(mfm_track_t));
-	fread(dev->tracks, 1, dev->total_tracks * sizeof(mfm_track_t), dev->f);
+	size = dev->total_tracks * sizeof(mfm_track_t);
+	if (fread(dev->tracks, 1, size, dev->f) != size)
+		fatal("mfm_load(): Error reading tracks\n");
     }
 
     /* The chances of finding a HxC MFM image of a single-sided thin track
diff --git a/src/floppy/fdd_td0.c b/src/floppy/fdd_td0.c
index 6762f78f5..2326b2aa4 100644
--- a/src/floppy/fdd_td0.c
+++ b/src/floppy/fdd_td0.c
@@ -262,7 +262,8 @@ state_data_read(td0dsk_t *state, uint8_t *buf, uint16_t size)
 	size = (image_size - state->fdd_file_offset) & 0xffff;
     if (fseek(state->fdd_file, state->fdd_file_offset, SEEK_SET) == -1)
 	fatal("TD0: Failed to seek in state_data_read()\n");
-    fread(buf, 1, size, state->fdd_file);
+    if (fread(buf, 1, size, state->fdd_file) != size)
+	fatal("TD0: Error reading data in state_data_read()\n");
     state->fdd_file_offset += size;
 
     return(size);
diff --git a/src/floppy/fdi2raw.c b/src/floppy/fdi2raw.c
index 03ddf460f..feb597ef9 100644
--- a/src/floppy/fdi2raw.c
+++ b/src/floppy/fdi2raw.c
@@ -2137,8 +2137,10 @@ int fdi2raw_loadtrack (FDI *fdi, uae_u16 *mfmbuf, uae_u16 *tracktiming, int trac
 
 	fdi->err = 0;
 	fdi->track_src_len = fdi->track_offsets[track + 1] - fdi->track_offsets[track];
-	fseek (fdi->file, fdi->track_offsets[track], SEEK_SET);
-	fread (fdi->track_src_buffer, fdi->track_src_len, 1, fdi->file);
+	if (fseek (fdi->file, fdi->track_offsets[track], SEEK_SET) == -1)
+		fatal("fdi2raw_loadtrack(): Error seeking to the beginning of the file\n");
+	if (fread (fdi->track_src_buffer, 1, fdi->track_src_len, fdi->file) != fdi->track_src_len)
+		fatal("fdi2raw_loadtrack(): Error reading data\n");
 	memset (fdi->track_dst_buffer, 0, MAX_DST_BUFFER);
 	fdi->track_dst_buffer_timing[0] = 0;
 
@@ -2177,7 +2179,7 @@ int fdi2raw_loadtrack (FDI *fdi, uae_u16 *mfmbuf, uae_u16 *tracktiming, int trac
 		zxx (fdi);
 		outlen = -1;
 
-	} else if (fdi->track_type < 0x10) {
+	} else if (fdi->track_type < 0x0f) {
 
 		decode_normal_track[fdi->track_type](fdi);
 		fix_mfm_sync (fdi);
diff --git a/src/rom.c b/src/rom.c
index cbb43a82b..17c31e3ba 100644
--- a/src/rom.c
+++ b/src/rom.c
@@ -183,8 +183,10 @@ rom_load_linear(wchar_t *fn, uint32_t addr, int sz, int off, uint8_t *ptr)
     }
 
     if (ptr != NULL) {
-	(void)fseek(f, off, SEEK_SET);
-	(void)fread(ptr+addr, sz, 1, f);
+	if (fseek(f, off, SEEK_SET) == -1)
+		fatal("rom_load_linear(): Error seeking to the beginning of the file\n");
+	if (fread(ptr+addr, 1, sz, f) != sz)
+		fatal("rom_load_linear(): Error reading data\n");
     }
 
     (void)fclose(f);
@@ -221,9 +223,12 @@ rom_load_linear_inverted(wchar_t *fn, uint32_t addr, int sz, int off, uint8_t *p
     }
 
     if (ptr != NULL) {
-	(void)fseek(f, off, SEEK_SET);
-	(void)fread(ptr+addr+0x10000, sz >> 1, 1, f);
-	(void)fread(ptr+addr, sz >> 1, 1, f);
+	if (fseek(f, off, SEEK_SET) == -1)
+		fatal("rom_load_linear_inverted(): Error seeking to the beginning of the file\n");
+	if (fread(ptr+addr+0x10000, 1, sz >> 1, f) > (sz >> 1))
+		fatal("rom_load_linear_inverted(): Error reading the upper half of the data\n");
+	if (fread(ptr+addr, sz >> 1, 1, f) > (sz >> 1))
+		fatal("rom_load_linear_inverted(): Error reading the lower half of the data\n");
     }
 
     (void)fclose(f);
diff --git a/src/scsi/scsi_cdrom.c b/src/scsi/scsi_cdrom.c
index cbe32f15a..201d597d2 100644
--- a/src/scsi/scsi_cdrom.c
+++ b/src/scsi/scsi_cdrom.c
@@ -450,7 +450,8 @@ scsi_cdrom_mode_sense_load(scsi_cdrom_t *dev)
 	swprintf(file_name, 512, L"cdrom_%02i_mode_sense_bin", dev->id);
     f = plat_fopen(nvr_path(file_name), L"rb");
     if (f) {
-	fread(dev->ms_pages_saved.pages[GPMODE_CDROM_AUDIO_PAGE], 1, 0x10, f);
+	if (fread(dev->ms_pages_saved.pages[GPMODE_CDROM_AUDIO_PAGE], 1, 0x10, f) != 0x10)
+		fatal("scsi_cdrom_mode_sense_load(): Error reading data\n");
 	fclose(f);
     }
 }
diff --git a/src/video/vid_ati18800.c b/src/video/vid_ati18800.c
index 648772c77..fa4b22044 100644
--- a/src/video/vid_ati18800.c
+++ b/src/video/vid_ati18800.c
@@ -86,6 +86,7 @@ static void ati18800_out(uint16_t addr, uint8_t val, void *p)
                 {
                         case 0xb0:
                         svga_recalctimings(svga);
+			break;
                         case 0xb2:
                         case 0xbe:
                         if (ati18800->regs[0xbe] & 8) /*Read/write bank mode*/
diff --git a/src/video/vid_im1024.c b/src/video/vid_im1024.c
index 6a297d9ca..00954e2d6 100644
--- a/src/video/vid_im1024.c
+++ b/src/video/vid_im1024.c
@@ -523,6 +523,10 @@ hndl_poly(pgc_t *pgc)
 #ifdef ENABLE_IM1024_LOG
 	im1024_log("IM1024: POLY: out of memory\n");
 #endif
+	if (x)
+		free(x);
+	if (y)
+		free(y);
 	return;
     }
 
diff --git a/src/video/video.c b/src/video/video.c
index 35ca81a33..1cbdfdac4 100644
--- a/src/video/video.c
+++ b/src/video/video.c
@@ -933,11 +933,15 @@ loadfont(wchar_t *s, int format)
 	case 1:		/* PC200 */
 		for (d = 0; d < 4; d++) {
 			/* There are 4 fonts in the ROM */
-			for (c = 0; c < 256; c++)	/* 8x14 MDA in 8x16 cell */
-				fread(&fontdatm[256*d + c][0], 1, 16, f);
+			for (c = 0; c < 256; c++) {	/* 8x14 MDA in 8x16 cell */
+				if (fread(&fontdatm[256*d + c][0], 1, 16, f) != 16)
+					fatal("loadfont(): Error reading 8x16 font in PC200 mode, c = %i\n", c);
+			}
 			for (c = 0; c < 256; c++) {	/* 8x8 CGA in 8x16 cell */
-				fread(&fontdat[256*d + c][0], 1, 8, f);
-				fseek(f, 8, SEEK_CUR);
+				if (fread(&fontdat[256*d + c][0], 1, 8, f) != 8)
+					fatal("loadfont(): Error reading 8x8 font in PC200 mode, c = %i\n", c);
+				if (fseek(f, 8, SEEK_CUR) == -1)
+					fatal("loadfont(): Error seeking in PC200 mode, c = %i\n", c);
 			}
 		}
 		break;
@@ -1015,7 +1019,7 @@ loadfont(wchar_t *s, int format)
 		/* The second 4k holds an 8x16 font */
 		for (c = 0; c < 256; c++) {
 			if (fread(&fontdatm[c][0], 1, 16, f) != 16)
-				fatal("loadfont(): Error reading font file in Sigma Coloar 400 mdoe, c = %i\n", c);
+				fatal("loadfont(): Error reading 8x16 font in Sigma Color 400 mode, c = %i\n", c);
 		}
 		break;