diff --git a/src/cdrom/cdrom.c b/src/cdrom/cdrom.c
index 3bfada9ec..a163c9390 100644
--- a/src/cdrom/cdrom.c
+++ b/src/cdrom/cdrom.c
@@ -295,7 +295,7 @@ msf_to_bcd(int *m, int *s, int *f)
 void
 cdrom_compute_ecc_block(cdrom_t *dev, uint8_t *parity, const uint8_t *data,
                         uint32_t major_count, uint32_t minor_count,
-                        uint32_t major_mult, uint32_t minor_inc)
+                        uint32_t major_mult, uint32_t minor_inc, int m2f1)
 {
     uint32_t size = major_count * minor_count;
 
@@ -308,6 +308,9 @@ cdrom_compute_ecc_block(cdrom_t *dev, uint8_t *parity, const uint8_t *data,
         for (uint32_t minor = 0; minor < minor_count; ++minor) {
             uint8_t temp = data[index];
 
+            if (m2f1 && (index < 4))
+                temp = 0x00;
+
             index += minor_inc;
 
             if (index >= size)
@@ -323,14 +326,14 @@ cdrom_compute_ecc_block(cdrom_t *dev, uint8_t *parity, const uint8_t *data,
     }
 }
 
-extern void
-cdrom_generate_ecc_data(cdrom_t *dev, const uint8_t *data)
+static void
+cdrom_generate_ecc_data(cdrom_t *dev, const uint8_t *data, int m2f1)
 {
     /* Compute ECC P code. */
-    cdrom_compute_ecc_block(dev, dev->p_parity, data, 86, 24, 2, 86);
+    cdrom_compute_ecc_block(dev, dev->p_parity, data, 86, 24, 2, 86, m2f1);
 
     /* Compute ECC Q code. */
-    cdrom_compute_ecc_block(dev, dev->q_parity, data, 52, 43, 86, 88);
+    cdrom_compute_ecc_block(dev, dev->q_parity, data, 52, 43, 86, 88, m2f1);
 }
 
 static int
@@ -338,21 +341,23 @@ cdrom_is_sector_good(cdrom_t *dev, const uint8_t *b, const uint8_t mode2, const
 {
     int            ret = 1;
 
-    if (mode2 && (form == 1)) {
-        const uint32_t crc = cdrom_crc32(0xffffffff, b, 2072) ^ 0xffffffff;
+    if (!mode2 || (form != 1)) {
+        if (mode2 && (form == 1)) {
+            const uint32_t crc = cdrom_crc32(0xffffffff, &(b[16]), 2056) ^ 0xffffffff;
 
-        ret = ret && (crc == (*(uint32_t *) &(b[2072])));
-    } else if (!mode2) {
-        const uint32_t crc = cdrom_crc32(0xffffffff, b, 2064) ^ 0xffffffff;
+            ret = ret && (crc == (*(uint32_t *) &(b[2072])));
+        } else if (!mode2) {
+            const uint32_t crc = cdrom_crc32(0xffffffff, b, 2064) ^ 0xffffffff;
 
-        ret = ret && (crc == (*(uint32_t *) &(b[2064])));
+            ret = ret && (crc == (*(uint32_t *) &(b[2064])));
+        }
+
+        cdrom_generate_ecc_data(dev, &(b[12]), mode2 && (form == 1));
+
+        ret = ret && !memcmp(dev->p_parity, &(b[2076]), 172);
+        ret = ret && !memcmp(dev->q_parity, &(b[2248]), 104);
     }
 
-    cdrom_generate_ecc_data(dev, &(b[12]));
-
-    ret = ret && !memcmp(dev->p_parity, &(b[2076]), 172);
-    ret = ret && !memcmp(dev->q_parity, &(b[2248]), 104);
-
     return ret;
 }
 
@@ -379,7 +384,7 @@ read_data(cdrom_t *dev, const uint32_t lba, int check)
                 else if (dev->raw_buffer[dev->cur_buf ^ 1][0x0012] ==
                          dev->raw_buffer[dev->cur_buf ^ 1][0x0016])
                     form = ((dev->raw_buffer[dev->cur_buf ^ 1][0x0012] &
-                        0x20) >> 5) + 1;
+                            0x20) >> 5) + 1;
             } else if (dev->raw_buffer[dev->cur_buf ^ 1][0x000f] == 0x02)
                 dev->mode2 = 1;
 
diff --git a/src/cdrom/cdrom_image.c b/src/cdrom/cdrom_image.c
index ccb2ebe09..ff1a913c3 100644
--- a/src/cdrom/cdrom_image.c
+++ b/src/cdrom/cdrom_image.c
@@ -19,7 +19,6 @@
 #define __STDC_FORMAT_MACROS
 #include <ctype.h>
 #include <inttypes.h>
-// #define ENABLE_IMAGE_LOG 1
 #ifdef ENABLE_IMAGE_LOG
 #include <stdarg.h>
 #endif
@@ -2045,7 +2044,7 @@ image_load_mds(cd_image_t *img, const char *mdsfile)
                 ci->file = tf;
             } else {
                 ci->start = (mds_trk_block.pm * 60 * 75) + (mds_trk_block.ps * 75) + mds_trk_block.pf;
-                ci->type = INDEX_ZERO;
+                ci->type = INDEX_NONE;
                 ci->file_start = 0;
                 ci->file_length = 0;
                 ci->file = NULL;
@@ -2309,28 +2308,21 @@ image_read_sector(const void *local, uint8_t *buffer,
             if ((ret > 0) && (trk->attr & 0x04) && ((idx->type < INDEX_NORMAL) || !track_is_raw)) {
                 uint32_t crc;
 
-                if ((trk->mode == 2) && (trk->form == 1))
-                    crc = cdrom_crc32(0xffffffff, buf, 2072) ^ 0xffffffff;
-                else
+                if ((trk->mode == 2) && (trk->form == 1)) {
+                    crc = cdrom_crc32(0xffffffff, &(buf[16]), 2056) ^ 0xffffffff;
+                    memcpy(&(buf[2072]), &crc, 4);
+                } else {
                     crc = cdrom_crc32(0xffffffff, buf, 2064) ^ 0xffffffff;
+                    memcpy(&(buf[2064]), &crc, 4);
+                }
 
-                memcpy(&(buf[2064]), &crc, 4);
+                int m2f1 = (trk->mode == 2) && (trk->form == 1);
 
-#if 0
                 /* Compute ECC P code. */
-                cdrom_compute_ecc_block(dev, dev->p_parity, &(buf[12]), 86, 24, 2, 86);
-                memcpy(&(buf[2076]), dev->p_parity, 172);
+                cdrom_compute_ecc_block(dev, &(buf[2076]), &(buf[12]), 86, 24, 2, 86, m2f1);
 
                 /* Compute ECC Q code. */
-                cdrom_compute_ecc_block(dev, dev->q_parity, &(buf[12]), 52, 43, 86, 88);
-                memcpy(&(buf[2248]), dev->q_parity, 104);
-#else
-                /* Compute ECC P code. */
-                cdrom_compute_ecc_block(dev, &(buf[2076]), &(buf[12]), 86, 24, 2, 86);
-
-                /* Compute ECC Q code. */
-                cdrom_compute_ecc_block(dev, &(buf[2248]), &(buf[12]), 52, 43, 86, 88);
-#endif
+                cdrom_compute_ecc_block(dev, &(buf[2248]), &(buf[12]), 52, 43, 86, 88, m2f1);
             }
 
             if ((ret > 0) && ((idx->type < INDEX_NORMAL) || (trk->subch_type != 0x08))) {
diff --git a/src/include/86box/cdrom.h b/src/include/86box/cdrom.h
index ebfc2722e..a031da199 100644
--- a/src/include/86box/cdrom.h
+++ b/src/include/86box/cdrom.h
@@ -459,7 +459,7 @@ extern void            cdrom_reload(const uint8_t id);
 
 extern void            cdrom_compute_ecc_block(cdrom_t *dev, uint8_t *parity, const uint8_t *data,
                                                uint32_t major_count, uint32_t minor_count,
-                                               uint32_t major_mult, uint32_t minor_inc);
+                                               uint32_t major_mult, uint32_t minor_inc, int m2f1);
 extern unsigned long   cdrom_crc32(unsigned long crc, const unsigned char *buf,
                                    size_t len);