Please help!!

[gh100l]

Please help!! ARM Data abort/prefetch issue again!
Okay... I had M3 88 and bought another one used recently here in Korea as a gift to my brother when I return to Australia.

It was version 1.xx and few days ago, I upgraded to v2.00 and got the infamous 'ARM CPU Data Abort Cached' message. I researched every threads possible to fix the problem. Not to mention the error message never came up before I upgraded the firmware.

Initially, the error message came up when I was browing the combi/prog. It came up kind of randomly when I selected combi/prog using 'bank select' buttons or dial. It even happened when I tried to select through the touch screen or during startup.
1. I tried "[Reset Control] + [1 ]+ [2]" to clear the data and reloaded factory setup : Did not solve.
2. Tried firmware upgrade to 2.05 : Did not solve the problem.
3. Replaced the SD card with the one from fully working M3(v2.05) : Did not solve the problem.
4. Downgraded to 2.00 and upgraded to 2.05 again : Did not solve the problem.
5. Went through Internal check as per service guide and everything was fine[test result was all OK].
6. "[EXIT] + [COMBI]" to format the SD card and replace it with data backed up from my other fully working m3: Did not solve the issue.

Now, my latest attempt was removing the battery. The problem got worse. Before I did this, the error message definitely came up when browsing but occasionally during powering on. After removing the battery for few minutes and replaced, it happens during powering on almost every time. and I also see 'ARM CPU Prefetch Abort Cached' message as well.

I contacted Korg dealer in Korea and they said they could not provide services as the machine was bought overseas....

I cannot find which data is corrupted and causing this problem.
Do I need to hard reset the m3 and replace the SD card with factory OS files?
I need help. Please help me...