diff --git a/mkbootimg/esp.c b/mkbootimg/esp.c
index 79f985d..1f1c24d 100644
--- a/mkbootimg/esp.c
+++ b/mkbootimg/esp.c
@@ -163,14 +163,17 @@ void esp_makepart()
     for(i = 0; i < NUMARCH && initrd_arch[i]; i++)
         boot |= (1 << (initrd_arch[i] - 1));
 
+    /* add loader's directory */
     ptr = esp_mkdir(rootdir, "BOOTBOOT", 0); rootdir += 32;
     if(boot & (1 << 1)) {
-        /* x86 PC (BIOS) */
+        /*** x86 PC (BIOS) ***/
+        /* start address has to be saved in PMBR too */
         esp_bbs = ((data + nextcluster * bpc)-esp) / 512;
         memcpy(esp + 0x1B0, &esp_bbs, 4);
         ptr = esp_addfile(ptr, "LOADER", binary_bootboot_bin, sizeof(binary_bootboot_bin));
     }
     ptr = esp_addfile(ptr, "CONFIG", (unsigned char*)config, strlen(config));
+    /* add INITRDs */
     if(!initrd_arch[1]) {
         ptr = esp_addfile(ptr, initrdnames[0], initrd_buf[0], initrd_size[0]);
     } else {
@@ -178,21 +181,33 @@ void esp_makepart()
             ptr = esp_addfile(ptr, initrdnames[(int)initrd_arch[i]], initrd_buf[i], initrd_size[i]);
         }
     }
+    if(boot & (1 << 6)) {
+        /* additional platform */
+    }
+    if(boot & (1 << 5)) {
+        /* additional platform */
+    }
+    if(boot & (1 << 4)) {
+        /* additional platform */
+    }
     if(boot & (1 << 3)) {
         /* additional platform */
     }
     if(boot & (1 << 2)) {
-        /* Risc-V 64 */
-        ptr = esp_addfile(rootdir, "KERNEL.IMG", binary_bootboot_rv64, sizeof(binary_bootboot_rv64));
+        /*** Risc-V 64 Microchip Icicle ***/
+        /* start and end address has to be added to the GPT too in a special partition */
+        bbp_start = ((data + nextcluster * bpc)-esp) / 512;
+        rootdir = esp_addfile(rootdir, "PAYLOAD.BIN", binary_bootboot_rv64, sizeof(binary_bootboot_rv64));
+        bbp_end = (((data + nextcluster * bpc)-esp) / 512) - 1;
     }
     if(boot & (1 << 1)) {
-        /* x86 PC (UEFI) */
+        /*** x86 PC (UEFI) ***/
         ptr = esp_mkdir(rootdir, "EFI", 0); rootdir += 32;
         ptr = esp_mkdir(ptr, "BOOT", lastcluster);
         ptr = esp_addfile(ptr, "BOOTX64.EFI", binary_bootboot_efi, sizeof(binary_bootboot_efi));
     }
     if(boot & (1 << 0)) {
-        /* Raspberry Pi */
+        /*** Raspberry Pi ***/
         ptr = esp_addfile(rootdir, "KERNEL8.IMG", binary_bootboot_img, sizeof(binary_bootboot_img));
         ptr = esp_addfile(ptr, "BOOTCODE.BIN", binary_bootcode_bin, sizeof(binary_bootcode_bin));
         ptr = esp_addfile(ptr, "FIXUP.DAT", binary_fixup_dat, sizeof(binary_fixup_dat));
diff --git a/mkbootimg/fs.h b/mkbootimg/fs.h
index aae78ad..e5940dd 100644
--- a/mkbootimg/fs.h
+++ b/mkbootimg/fs.h
@@ -61,7 +61,6 @@ fsdrv_t fsdrv[] = {
     { "ufs",                     { 0x516E7CB6, 0x6ECF, 0x11D6, { 0x8F,0xF8,0x00,0x02,0x2D,0x09,0x71,0x2B} }, NULL, NULL, NULL },
     { "p9",                      { 0xC91818F9, 0x8025, 0x47AF, { 0x89,0xD2,0xF0,0x30,0xD7,0x00,0x0C,0x2C} }, NULL, NULL, NULL },
     { "Intel Fast Flash",        { 0xD3BFE2DE, 0x3DAF, 0x11DF, { 0xBA,0x40,0xE3,0xA5,0x56,0xD8,0x95,0x93} }, NULL, NULL, NULL },
-    { "BIOS boot",               { 0x21686148, 0x6449, 0x6E6F, { 0x74,0x4E,0x65,0x65,0x64,0x45,0x46,0x49} }, NULL, NULL, NULL },
     { "Sony boot partition",     { 0xF4019732, 0x066E, 0x4E12, { 0x82,0x73,0x34,0x6C,0x56,0x41,0x49,0x4F} }, NULL, NULL, NULL },
     { "Lenovo boot partition",   { 0xBFBFAFE7, 0xA34F, 0x448A, { 0x9A,0x5B,0x62,0x13,0xEB,0x73,0x6C,0x22} }, NULL, NULL, NULL },
     { "PowerPC PReP boot",       { 0x9E1A2D38, 0xC612, 0x4316, { 0xAA,0x26,0x8B,0x49,0x52,0x1E,0x5A,0x8B} }, NULL, NULL, NULL },
diff --git a/mkbootimg/gpt.c b/mkbootimg/gpt.c
index 7db560f..196fa8a 100644
--- a/mkbootimg/gpt.c
+++ b/mkbootimg/gpt.c
@@ -30,9 +30,10 @@
 #include "main.h"
 
 guid_t efiguid = { 0xC12A7328, 0xF81F, 0x11D2, { 0xBA,0x4B,0x00,0xA0,0xC9,0x3E,0xC9,0x3B} };
+guid_t bbpguid = { 0x21686148, 0x6449, 0x6E6F, { 0x74,0x4E,0x65,0x65,0x64,0x45,0x46,0x49} };
 unsigned char *gpt = NULL, gpt2[512];
 unsigned long int gpt_parts[248];
-int np = 0;
+int np = 0, bbp_start = 0, bbp_end = 0;
 
 /**
  * Set integers in byte arrays
@@ -61,6 +62,7 @@ void gpt_maketable()
     total = (2*es + esiz) * 512;
     memset(gpt_parts, 0, sizeof(gpt_parts));
     for(np = 1; np < 248; np++) {
+        /* get type, either fsname or GUID */
         sprintf(key, "partitions.%d.%s", np, "type");
         tmp = json_get(json, key);
         if(!tmp || !*tmp) break;
@@ -68,11 +70,11 @@ void gpt_maketable()
         for(i = 0; fsdrv[i].name; i++)
             if(fsdrv[i].type.Data1 && !strcmp(tmp, fsdrv[i].name)) { memcpy(&typeguid, &fsdrv[i].type, sizeof(guid_t)); break; }
         free(tmp);
-        if(!typeguid.Data1 && !typeguid.Data2 && !typeguid.Data3 && !typeguid.Data4[0]) {
-            sprintf(key, "partitions.%d.%s", np, "typeguid");
-            tmp = json_get(json, key);
-            if(tmp && *tmp) { getguid(tmp, &typeguid); free(tmp); }
-        }
+        /* override with specific GUID if type was an fsname */
+        sprintf(key, "partitions.%d.%s", np, "typeguid");
+        tmp = json_get(json, key);
+        if(tmp && *tmp) { getguid(tmp, &typeguid); free(tmp); }
+        /* if there's still no type GUID */
         if(!typeguid.Data1 && !typeguid.Data2 && !typeguid.Data3 && !typeguid.Data4[0]) {
             fprintf(stderr,"mkbootimg: partition #%d %s. %s:\r\n", np+1, lang[ERR_TYPE], lang[ERR_ACCEPTVALUES]);
             for(i = 0; fsdrv[i].name; i++)
@@ -85,10 +87,12 @@ void gpt_maketable()
             fprintf(stderr,"  ...%s \"%%08X-%%04X-%%04X-%%04X-%%12X\"\r\n",lang[ERR_GUIDFMT]);
             exit(1);
         }
+        /* partition's name */
         sprintf(key, "partitions.%d.%s", np, "name");
         tmp = json_get(json, key);
         if(!tmp || !*tmp) { fprintf(stderr,"mkbootimg: partition #%d %s\r\n", np+1, lang[ERR_NONAME]); exit(1); }
         free(tmp);
+        /* size and/or image file's size */
         sprintf(key, "partitions.%d.%s", np, "size");
         tmp = json_get(json, key); if(tmp) { size = atoi(tmp) * 1024UL * 1024UL; } else { size = 0; } free(tmp);
         sprintf(key, "partitions.%d.%s", np, "file");
@@ -173,6 +177,20 @@ void gpt_maketable()
     for(i = 0; name[i]; i++) p[56+i*2] = name[i];
     p += 128;
 
+    /* BIOS BOOT Partition (needed for Risc-V64 Icicle firmware, not mounted, binary blob) */
+    if(bbp_start && bbp_end && bbp_start <= bbp_end) {
+        /* it would have been more fortunate if Microchip had choosen its own Microchip boot partition type guid */
+        memcpy(p, &bbpguid, sizeof(guid_t));        /* entry type */
+        diskguid.Data1++;
+        memcpy(p+16, &diskguid, sizeof(guid_t));    /* partition UUID */
+        setint(bbp_start,p+32);                     /* start LBA */
+        setint(bbp_end,p+40);                       /* end LBA */
+        name = "BOOTBOOT RISC-V";                   /* name */
+        for(i = 0; name[i]; i++) p[56+i*2] = name[i];
+        p += 128;
+    }
+
+    /* add user defined partitions */
     for(k = 1; k < np; k++) {
         sprintf(key, "partitions.%d.%s", k, "type");
         tmp = json_get(json, key);
@@ -181,15 +199,15 @@ void gpt_maketable()
         for(i = 0; fsdrv[i].name; i++)
             if(fsdrv[i].type.Data1 && !strcmp(tmp, fsdrv[i].name)) { memcpy(&typeguid, &fsdrv[i].type, sizeof(guid_t)); break; }
         free(tmp);
-        memcpy(p, &typeguid, sizeof(guid_t));        /* entry type */
+        memcpy(p, &typeguid, sizeof(guid_t));       /* entry type */
         diskguid.Data1++;
-        memcpy(p+16, &diskguid, sizeof(guid_t));     /* partition UUID */
-        setint(l+1,p+32);                            /* start LBA */
+        memcpy(p+16, &diskguid, sizeof(guid_t));    /* partition UUID */
+        setint(l+1,p+32);                           /* start LBA */
         l += gpt_parts[k] / 512;
-        setint(l,p+40);                              /* end LBA */
+        setint(l,p+40);                             /* end LBA */
         sprintf(key, "partitions.%d.%s", k, "name"); tmp = name = json_get(json, key);
         u = (uint16_t*)(p+56);
-        for(i = 0; i < 35 && *name; name++, i++) {   /* name, utf8 to unicode16 */
+        for(i = 0; i < 35 && *name; name++, i++) {  /* name, utf8 to unicode16 */
             u[i] = *name;
             if((*name & 128) != 0) {
                 if(!(*name & 32)) { u[i] = ((*name & 0x1F)<<6)|(name[1] & 0x3F); name += 1; } else
diff --git a/mkbootimg/main.c b/mkbootimg/main.c
index 1168f75..3eee321 100644
--- a/mkbootimg/main.c
+++ b/mkbootimg/main.c
@@ -434,7 +434,7 @@ int main(int argc, char **argv)
                 "  ./mkbootimg <%s> <%s>\r\n\r\n",lang[HELP3],lang[HELP4],
                 lang[HELP4],lang[HELP4],lang[HELP5]);
         printf( "%s:\n"
-                "  ./mkbootimg check mykernel/mykernel.x86_64.elf\r\n"
+                "  ./mkbootimg check mykernel/c/mykernel.x86_64.elf\r\n"
                 "  ./mkbootimg myos.json initrd.rom\r\n"
                 "  ./mkbootimg myos.json bootpart.bin\r\n"
                 "  ./mkbootimg myos.json myos.img\r\n",
diff --git a/mkbootimg/main.h b/mkbootimg/main.h
index 0a9f31b..c9f0d00 100644
--- a/mkbootimg/main.h
+++ b/mkbootimg/main.h
@@ -185,7 +185,7 @@ extern time_t t;
 extern struct tm *ts;
 extern guid_t diskguid;
 extern char *json, *config, *kernelname, *initrd_dir[NUMARCH], initrd_arch[NUMARCH];
-extern int fs_len, initrd_size[NUMARCH], initrd_gzip, boot_size, boot_fat, disk_size, esp_size, esp_bbs;
+extern int fs_len, initrd_size[NUMARCH], initrd_gzip, boot_size, boot_fat, disk_size, esp_size, esp_bbs, bbp_start, bbp_end;
 extern int iso9660, skipbytes, np;
 extern unsigned char *esp, *gpt, gpt2[512], *fs_base, *initrd_buf[NUMARCH];
 extern unsigned long int tsize, es, esiz, disk_align, gpt_parts[248];
diff --git a/riscv64-icicle/README.md b/riscv64-icicle/README.md
index 6d38413..484d2bc 100644
--- a/riscv64-icicle/README.md
+++ b/riscv64-icicle/README.md
@@ -4,3 +4,8 @@ BOOTBOOT MicroChip Icicle Risc-V64 Implementation
 See [BOOTBOOT Protocol](https://gitlab.com/bztsrc/bootboot) for common details.
 
 Currently __EXPERIMENTAL__.
+
+Generates dist/bootboot.rv64, should include Risc-V hart config and bootboot.elf and use the same format as
+https://github.com/polarfire-soc/hart-software-services/tree/master/tools/hss-payload-generator
+
+mkbootimg already knows what to do with that file, but currently installs an empty blob.