TL;DR

• A Crucial BX500 (SM2259XT + Micron B47R) stuck in a "silent read-only" state was revived with SMI MPTool.
• It worked over a normal motherboard SATA port in AHCI mode: no ROM mode, no pad shorting, no USB adapter.
• The key was forcing MPTool to use the ATA-DMA transport instead of the default SAT-DMA (settings below).
• Also posted on usbdev.ru: https://www.usbdev.ru/f/index.php?topic=14100.0

1. Hardware

• SSD: Crucial BX500 480GB (CT480BX500SSD1), Crucial firmware M6CR052, made in 2021.
• Controller: SM2259XT, DRAM-less.
• NAND: Micron 176-layer B47R TLC, FlashID 2C C3 08 32 EA 30, 8 dies, 4 channels.
• PC: Gigabyte Z790 (Intel 700-series chipset), SATA in AHCI mode, Microsoft storahci driver, Windows 11. This chipset has no IDE mode.

2. Symptoms
The drive accepted every write, but everything rolled back after each power cycle.

• New files disappeared after a reboot.
• Format, Crucial firmware update and Sanitize (Storage Executive) all said "success", then were undone at the next power cycle.
• SMART counters were frozen: the power cycle count never increased, and total LBAs written went backwards.
• SMART said "FAILED - failure expected in less than 24 hours", but no attribute was below its threshold.
• The NAND itself was healthy: 0 reallocated blocks, 0 program/erase failures, 12% wear.

Likely cause: the FTL froze after a power loss (942 unexpected power losses on the counter).

3. Package used

Default configuration kept: IMB47 profile, auto capacity, Download ISP, Pretest "Reference Original Bad".
Note: the U0312B package for B47R did not detect the drive either with default settings.

4. The problem: MPTool did not detect the drive
With default settings, every port showed "N". Nothing helped: blank drive after Sanitize, drive letter removed, Windows compatibility mode, other AutoPortMapping values.
Reason: by default MPTool uses the "SAT-DMA" transport. It is meant for USB-SATA bridges and does not work on a native AHCI controller.

5. The fix: force the ATA-DMA transport
Changing only PassThroughType was not enough, because the executable chooses its transport afterwards and can override it.

Step 1. In UFD_MP\Setting.set, add these lines under the existing [OPTION] section:


Step 2. In UFD_MP\SMIPortMappingEx.ini, set these keys inside their existing sections. Do not replace the whole file.


Step 3. Close MPTool and open it again as administrator. The status bar now shows "ATA-DMA" instead of "SAT-DMA".

Step 4. Click Scan Drive. Result:

The drive still identified as a normal Crucial. No hardware change was needed.

6. Reflash result

• Programming ended with "Check ISP Mode fail (7A)".
• But the log showed a successful GPIO check (other BX500 owners on usbdev.ru got "GPIO Check fail (18)/(3C.01)") and firmware writes with matching checksums.
• After a 30-second power cut, the drive booted with the generic firmware U0524A0 (model "SSD", serial AA000000000000001285).

7. Checks after the repair

• SMART: PASSED, no errors logged, power cycle count increasing again.
• Persistence: 1 GiB of test files had identical SHA-256 after two power cycles, including 13 hours powered off.
• Full capacity test: 446 files of 1 GiB (445.5 GiB of different random data) written with no errors. After a power cut, all 446 files had identical SHA-256.
• After the test: still 15 bad blocks (the factory ones), 0 program/erase failures, wear evenly spread.
• Speed: about 300 MB/s in the SLC cache, about 70 MB/s when the cache is full (normal for this DRAM-less drive). Read speed about 450 MB/s.
• TRIM works.

8. Limitations

• I did not test whether each of the three Setting.set options, or CheckDeviceType=3, is needed on its own. The full combination is what worked.
• One drive, one platform only (Intel Z790, AHCI, storahci).
• Long-term data retention is not verified yet.

9. Warnings

• MPTool erases everything and permanently replaces the Crucial firmware: no more Storage Executive, no Crucial updates, no warranty. This is not a data recovery method.
• The package must match your NAND exactly. Check it first with SMI Flash ID. A wrong package can brick the drive.
• Keep SkipSystemDrive=1 and check the detected port before clicking Start.

10. SMI Flash ID report (before reflash)


Hope this helps others.

Nice work, and many thanks for the write-up!

_________________
A backup a day keeps DR away.