diff --git a/src/mame/drivers/feversoc.c b/src/mame/drivers/feversoc.c
index e5c00cb1d37..93369de5d54 100644
--- a/src/mame/drivers/feversoc.c
+++ b/src/mame/drivers/feversoc.c
@@ -336,9 +336,7 @@ ROM_END
 
 static DRIVER_INIT( feversoc )
 {
-//	seibuspi_text_decrypt(memory_region(machine, "gfx1"));
-//	seibuspi_bg_decrypt(memory_region(machine, "gfx2"), memory_region_length(machine, "gfx2"));
-	seibuspi_rise11_sprite_decrypt(memory_region(machine, "gfx1"), 0x200000); //WRONG!
+	seibuspi_rise11_sprite_decrypt_feversoc(memory_region(machine, "gfx1"), 0x200000);
 }
 
 GAME( 2000, feversoc,  0,       feversoc,  feversoc,  feversoc, ROT0, "Seibu", "Fever Soccer", GAME_IMPERFECT_GRAPHICS | GAME_NOT_WORKING )
diff --git a/src/mame/drivers/seibuspi.c b/src/mame/drivers/seibuspi.c
index d2b45971305..4b7dbbe2869 100644
--- a/src/mame/drivers/seibuspi.c
+++ b/src/mame/drivers/seibuspi.c
@@ -2037,7 +2037,7 @@ static DRIVER_INIT( rfjet )
 	memory_install_read32_handler(cpu_get_address_space(machine->cpu[0], ADDRESS_SPACE_PROGRAM), 0x002894c, 0x002894f, 0, 0, rfjet_speedup_r );
 	seibuspi_rise11_text_decrypt(memory_region(machine, "gfx1"));
 	seibuspi_rise11_bg_decrypt(memory_region(machine, "gfx2"), memory_region_length(machine, "gfx2"));
-	seibuspi_rise11_sprite_decrypt(memory_region(machine, "gfx3"), 0x800000);
+	seibuspi_rise11_sprite_decrypt_rfjet(memory_region(machine, "gfx3"), 0x800000);
 
 	memory_install_write32_handler(cpu_get_address_space(machine->cpu[0], ADDRESS_SPACE_PROGRAM), 0x560, 0x563, 0, 0, sprite_dma_start_w);
 }
diff --git a/src/mame/includes/seibuspi.h b/src/mame/includes/seibuspi.h
index 8763bdd0049..7e4c9e1de94 100644
--- a/src/mame/includes/seibuspi.h
+++ b/src/mame/includes/seibuspi.h
@@ -19,7 +19,8 @@ void seibuspi_rise10_sprite_decrypt(UINT8 *rom, int romsize);
 
 void seibuspi_rise11_text_decrypt(UINT8 *rom);
 void seibuspi_rise11_bg_decrypt(UINT8 *rom, int size);
-void seibuspi_rise11_sprite_decrypt(UINT8 *rom, int romsize);
+void seibuspi_rise11_sprite_decrypt_rfjet(UINT8 *rom, int romsize);
+void seibuspi_rise11_sprite_decrypt_feversoc(UINT8 *rom, int romsize);
 
 
 /*----------- defined in video/seibuspi.c -----------*/
diff --git a/src/mame/machine/seibuspi.c b/src/mame/machine/seibuspi.c
index 0fa35b59da8..36f893b3f3e 100644
--- a/src/mame/machine/seibuspi.c
+++ b/src/mame/machine/seibuspi.c
@@ -303,10 +303,31 @@ cpu #0 (PC=002C40F9): unmapped program memory dword write to 0000054C = 00000300
         plane543 = partial_carry_sum24( plane543, 0x01cb64, 0x01aadd ) ^ 0x016a4c;
         plane210 = partial_carry_sum24( plane210,        i, 0xd6375b ) ^ 0x8bf23b;
 
+feversoc
+
+CPU 'main' (PC=00021C74): unmapped program memory dword write to 0601004C = D5A90000 & FFFF0000
+CPU 'main' (PC=00021C74): unmapped program memory dword write to 0601004C = 4EB50000 & FFFF0000
+CPU 'main' (PC=00021C74): unmapped program memory dword write to 0601004C = 9A4A0000 & FFFF0000
+CPU 'main' (PC=00021C74): unmapped program memory dword write to 0601004C = ADB30000 & FFFF0000
+CPU 'main' (PC=00021C74): unmapped program memory dword write to 0601004C = E9320000 & FFFF0000 //
+CPU 'main' (PC=00021C74): unmapped program memory dword write to 0601004C = 9DF50000 & FFFF0000
+CPU 'main' (PC=00021C74): unmapped program memory dword write to 0601004C = 99E90000 & FFFF0000 //
+CPU 'main' (PC=00021C74): unmapped program memory dword write to 0601004C = B2590000 & FFFF0000
+CPU 'main' (PC=00021C74): unmapped program memory dword write to 0601004C = 961D0000 & FFFF0000 //
+CPU 'main' (PC=00021C74): unmapped program memory dword write to 0601004C = 8B970000 & FFFF0000 //
+CPU 'main' (PC=00021C74): unmapped program memory dword write to 0601004C = EAAE0000 & FFFF0000
+CPU 'main' (PC=00021C74): unmapped program memory dword write to 0601004C = D5AC0000 & FFFF0000 //
+CPU 'main' (PC=00021C74): unmapped program memory dword write to 0601004C = 03000000 & FFFF0000
+
+        plane543 = partial_carry_sum24( plane543, 0x18f5b2, 0x18e999 ) ^ 0x3032e9;
+        plane210 = partial_carry_sum24( plane210,        i, 0x968bd5 ) ^ 0x1d97ac;
+        plane210 = partial_carry_sum24( plane210,        1, 0x000001 );
+
 ******************************************************************************************/
 
 
-void seibuspi_rise11_sprite_decrypt(UINT8 *rom, int size)
+void seibuspi_rise11_sprite_decrypt(UINT8 *rom, int size,
+	UINT32 k1, UINT32 k2, UINT32 k3, UINT32 k4, UINT32 k5, int feversoc_kludge)
 {
 	int i;
 
@@ -369,8 +390,10 @@ void seibuspi_rise11_sprite_decrypt(UINT8 *rom, int size)
 					(BIT(b1, 5)<<22) |
 					(BIT(b3,15)<<23);
 
-		plane543 = partial_carry_sum24( plane543, 0x01cb64, 0x01aadd ) ^ 0x016a4c;
-		plane210 = partial_carry_sum24( plane210,        i, 0xd6375b ) ^ 0x8bf23b;
+		plane543 = partial_carry_sum24( plane543, k1, k2 ) ^ k3;
+		plane210 = partial_carry_sum24( plane210,  i, k4 ) ^ k5;
+		if (feversoc_kludge)
+			plane210 = partial_carry_sum24( plane210,  1, 0x000001 );
 
 		rom[0*size+2*i]   = plane543 >> 16;
 		rom[0*size+2*i+1] = plane543 >>  8;
@@ -387,3 +410,15 @@ void seibuspi_rise11_sprite_decrypt(UINT8 *rom, int size)
 		sprite_reorder(&rom[2*size+2*i]);
 	}
 }
+
+
+void seibuspi_rise11_sprite_decrypt_rfjet(UINT8 *rom, int size)
+{
+	seibuspi_rise11_sprite_decrypt(rom, size, 0x01cb64, 0x01aadd, 0x016a4c, 0xd6375b, 0x8bf23b, 0);
+}
+
+
+void seibuspi_rise11_sprite_decrypt_feversoc(UINT8 *rom, int size)
+{
+	seibuspi_rise11_sprite_decrypt(rom, size, 0x18f5b2, 0x18e999, 0x3032e9, 0x968bd5, 0x1d97ac, 1);
+}