On the 4pda forum, a user reported that during the CSC change process on a European Samsung device, the process would constantly fail on both Step 1 and Step 3. Despite repeated attempts, they could not change the region back from a Korean region to EUX.
If you are reading this, you have likely encountered the dreaded red text in the SAMFW Tool: samfw running exploit fail
Method 3: Flash Official Regional Firmware via Odin (No Data Loss) On the 4pda forum, a user reported that
Find an older firmware version for your exact phone model that features a vulnerable security patch level. If the popup does not appear, turn USB
If the popup does not appear, turn USB Debugging off and on again in Developer Options . 4. Use the Correct Test Mode Method
Changing CSC configurations safely on patched security firmware. If you need help proceeding, please let me know: What is your exact Samsung (e.g., SM-S928B)?