diff --git a/src/devices/bus/saitek_osa/sparc.cpp b/src/devices/bus/saitek_osa/sparc.cpp
index 7bc67093d48..8fb7ec0537a 100644
--- a/src/devices/bus/saitek_osa/sparc.cpp
+++ b/src/devices/bus/saitek_osa/sparc.cpp
@@ -11,6 +11,11 @@ Hardware notes:
 - Fujitsu MB86930-20 SPARClite @ 20MHz
 - 256KB ROM (4*AMD AM27C512)
 - 1MB DRAM (8*NEC 424256-60), expandable to 4MB
+- ESAN 31A-5500 delay line (only on newer PCB)
+
+Two PCB revisions are known, the older one is a lighter green PCB, it has
+empty positions for more ICs (maybe expanded RAM?), and does not have a
+delay line chip.
 
 The module doesn't have its own LCD screen. It has a grill+fan underneath
 at the front part, and a heatsink on the CPU.
diff --git a/src/mame/drivers/saitek_leonardo.cpp b/src/mame/drivers/saitek_leonardo.cpp
index 8037784733f..85b06b02aba 100644
--- a/src/mame/drivers/saitek_leonardo.cpp
+++ b/src/mame/drivers/saitek_leonardo.cpp
@@ -9,10 +9,10 @@ This is SciSys's answer to H+G Mephisto modular chesscomputers, but unlike the
 Mephistos, these boards are actual chesscomputers and not an accessory.
 
 They called the expansion capability "OSA", for "Open Systems Architecture".
-One for a link port to a PC, and one for a module slot. The expansion modules
-are basically entire chesscomputers, making the whole thing combined a
-'dual brain' chesscomputer. The embedded chess engine is by Julio Kaplan
-and Craig Barnes, same as the one in SciSys Turbo S-24K.
+A serial port for linking to a PC, and a parallel port for expansion modules.
+The expansion modules are basically entire chesscomputers, making the whole
+thing combined a 'dual brain' chesscomputer. The embedded chess engine is by
+Julio Kaplan and Craig Barnes, same as the one in SciSys Turbo S-24K.
 
 Hardware notes:
 
@@ -35,15 +35,18 @@ Galileo PCB is different, but essentially it's the same hardware as Leonardo.
 The 1.4 ROM is identical to it too, even though it's a different MCU type.
 And on the outside, the button panel was redesigned a bit.
 
-Expansion modules released:
+Known expansion modules:
 - Maestro (65C02, Kaplan/Barnes)
 - Analyst (65C02, Kaplan/Barnes)
+- Brute Force (prototype) (65C02?, Ulf Rathsman)
 - Brute Force (H8, Frans Morsch)
 - Sparc (SPARClite, Spracklen's)
 
-The Sparc module doesn't appear to work on the 1st program version of Leonardo.
-Moreover, the Sparc module manual mentions that for it to work properly on Leonardo,
-the chesscomputer needs to be upgraded with an EMI PCB (power supply related).
+The H8 Brute Force module doesn't work with the 1st program version of Leonardo,
+this is mentioned in the repair manual and it says it requires an EPROM upgrade.
+The Sparc module doesn't appear to work with it either. Moreover, the Sparc module
+manual mentions that for it to work properly on Leonardo, the chesscomputer needs
+to be upgraded with an EMI PCB (power supply related).
 
 TODO:
 - OSA module comms is not completely understood