Last year, I saw the 37c3 modchip and then found @PoroCYon(PCY)'s blog.
Where one of the posts displayed the DSi Panda motherboard. It had an 'LR359A12' CPU on it
(the retail version of the DSi uses the 'CPU TWL' or 'CPU TWL A').
A comment that says this CPU is being sold online. I found the dealer, and when I saw they had it in stock, I bought some. But I don't have a fully functional spare board, so I haven't replaced them.
Although I have a DSi Panda, I never knew it had a 'LR359A12' CPU, and there is no related information online.
Later I saw that PCY uploaded photos of the IS-TWL-DEBUGGER motherboard, and its CPU is also the 'LR359A12'.
So it seems that this is a CPU dedicated to development machines?
---------
UPDATE: (time-saving conclusion)
According to #7 & #12, I think 'LR359A12' ≈ 'CPU TWL', early production model.
'CPU TWL' was used for early retail DSi, while 'LR359A12' was used for development DSi.
'CPU TWL A' is a later production model, for later retail version DSi. Its development version is 'LR359A22' #27.
---------
(The following content is arranged in the order of my personal timeline, so it might be a bit confusing.)
I noticed there are some differences between the substrate of 'CPU TWL A' and 'LR359A12'.


Are there any other differences between these two CPUs?
.
Not long ago, one of my unused DSi had a graphical glitches, it seems the CPU has a cold solder joint.
I went ahead and replaced it, just for fun
(Click the image to view original)


The CPU I replaced
- CPU: LR359A12 , "0923 3m", produced in 2009/06?, console ID:
.
Then I had a professional take CPU dieshot.
(The CPU size is measured manually and may have some error)



The CPU on the right
- CPU: TWL A , "0944 7K", produced in 2009/10?, console ID:
- iQue DSi, TCF100264951
- board C/TWL-CPU-10
- Wireless card DWM-W024
- eMMC CID:
The CPU on the left
- CPU: LR359A12 , "0925 4m", produced in 2009/06?, console ID:08A*, substrate number "D2"
.
.
.
This afternoon, I received dieshot.
(The original image is very large, and I don't know the forum's upload limits, so I resized the image)
(Click the image to view)


They are indeed different
.
The core of the ‘LR359A12’ is larger than that of ‘CPU TWL A’.
...LR359A12 (left)......CPU TWL A (right)...


...LR359A12 (left)......CPU TWL A (right)...


.
Details (LR359A12): It might be made by Sharp?



Details (CPU TWL A): It might be made by Fujitsu?



.
.
Additional note: (Edited)
(I was mistaken before(i'm a noob), efuse only exists in the CPU, and MBR is related to NAND encryption.)
Since the Console ID (CPU ID) is used to initialize KEY_X values for eMMC encryption/decryption [1], the original NAND becomes useless after replacing the CPU.
If you only replace the CPU, ntrboot can launch some homebrew software(e.g. godmode9i, hbmenu, safenandmanager) that doesn't check the MBR, then using slot1launch can boot DS/DSi cartridge and flashcards (without sound&wifi, same situation when using ntrboot to launch slot1launch on a retail DSi).
[1] Martin Korth. GBATEK, DSi Console IDs
.
.
UPDATE
Related to 'LR359A12' CPU:
- Make a DSi panda ‘clone’
.
#14
- Transform the DSi panda 'clone' into a ‘real’ DSi panda clone
.
#16
- Install the system from zero, make a real DSi panda
.
#17 
- IR photo of 'LR359A12'.
#26
- Dieshot of 'LR359A12'.
#30
Related to 'LR359A22' CPU:
- The development version of 'CPU TWL A'.
#27
Related to DSi panda:
-
#17, #18
- DSi panda's slot1launch.
#20
#21
- Install TWiLightMenu++ and SD card's Unlaunch when using the prototype menu.
#25
- SignaPicDSi for dev
(DSi panda)
- Install unlaunch on development units (pandas) (rvtr's tutorial)
Where one of the posts displayed the DSi Panda motherboard. It had an 'LR359A12' CPU on it
A comment that says this CPU is being sold online. I found the dealer, and when I saw they had it in stock, I bought some. But I don't have a fully functional spare board, so I haven't replaced them.
Although I have a DSi Panda, I never knew it had a 'LR359A12' CPU, and there is no related information online.
Later I saw that PCY uploaded photos of the IS-TWL-DEBUGGER motherboard, and its CPU is also the 'LR359A12'.
So it seems that this is a CPU dedicated to development machines?
---------
UPDATE: (time-saving conclusion)
According to #7 & #12, I think 'LR359A12' ≈ 'CPU TWL', early production model.
'CPU TWL' was used for early retail DSi, while 'LR359A12' was used for development DSi.
'CPU TWL A' is a later production model, for later retail version DSi. Its development version is 'LR359A22' #27.
---------
(The following content is arranged in the order of my personal timeline, so it might be a bit confusing.)
I noticed there are some differences between the substrate of 'CPU TWL A' and 'LR359A12'.


Are there any other differences between these two CPUs?
.
Not long ago, one of my unused DSi had a graphical glitches, it seems the CPU has a cold solder joint.
I went ahead and replaced it, just for fun
(Click the image to view original)


The CPU I replaced
- CPU: LR359A12 , "0923 3m", produced in 2009/06?, console ID:
08A2277024096132.
Then I had a professional take CPU dieshot.
(The CPU size is measured manually and may have some error)



The CPU on the right
- CPU: TWL A , "0944 7K", produced in 2009/10?, console ID:
0820150305099126- iQue DSi, TCF100264951
- board C/TWL-CPU-10
- Wireless card DWM-W024
- eMMC CID:
BC847011EF034D303046504100001500, produced in 2009/11, NAND product.log date 2010/01/25The CPU on the left
- CPU: LR359A12 , "0925 4m", produced in 2009/06?, console ID:08A*, substrate number "D2"
.
.
.
This afternoon, I received dieshot.
(The original image is very large, and I don't know the forum's upload limits, so I resized the image)
(Click the image to view)


They are indeed different
The core of the ‘LR359A12’ is larger than that of ‘CPU TWL A’.
...LR359A12 (left)......CPU TWL A (right)...


...LR359A12 (left)......CPU TWL A (right)...


.
Details (LR359A12): It might be made by Sharp?



Details (CPU TWL A): It might be made by Fujitsu?



.
.
Additional note: (Edited)
(I was mistaken before(i'm a noob), efuse only exists in the CPU, and MBR is related to NAND encryption.)
Since the Console ID (CPU ID) is used to initialize KEY_X values for eMMC encryption/decryption [1], the original NAND becomes useless after replacing the CPU.
If you only replace the CPU, ntrboot can launch some homebrew software(e.g. godmode9i, hbmenu, safenandmanager) that doesn't check the MBR, then using slot1launch can boot DS/DSi cartridge and flashcards (without sound&wifi, same situation when using ntrboot to launch slot1launch on a retail DSi).
[1] Martin Korth. GBATEK, DSi Console IDs
.
.
UPDATE
Related to 'LR359A12' CPU:
- Make a DSi panda ‘clone’
. - Transform the DSi panda 'clone' into a ‘real’ DSi panda clone
. - Install the system from zero, make a real DSi panda
. - IR photo of 'LR359A12'.
- Dieshot of 'LR359A12'.
Related to 'LR359A22' CPU:
- The development version of 'CPU TWL A'.
Related to DSi panda:
-
- DSi panda's slot1launch.
- Install TWiLightMenu++ and SD card's Unlaunch when using the prototype menu.
- SignaPicDSi for dev
- Install unlaunch on development units (pandas) (rvtr's tutorial)
Last edited by k66,











And to everyone who helped me, thank you.











































































