事情是这样的，我的st-link前几天不能用了，电脑读不出来。显示是未知设备（已安装st-link驱动）。想着可能是固件坏了。于是重刷固件，从网上找的固件hex文件。用J-FLASH 烧录。链接正常：Opening data file [C:UsersAdministratorDesktopSTLINK_JLINKob-STM32.hex] ...
- Data file opened successfully (63336 bytes, 3 ranges, CRC = 0xAC6E64AA)
Connecting ...
- Connecting via USB to J-Link device 0
- J-Link firmware: V1.20 (J-Link ARM-OB STM32 compiled Aug 22 2012 19:52:04)
- Target interface speed: 200 kHz (Auto)
- Initializing CPU core (Init sequence) ...
    - Initialized successfully
- Target interface speed: 200 kHz (Auto)
- Connected successfully

烧录错误：
Programming target (63336 bytes, 3 ranges) ... - ERROR: RAM check failed @ address 0x20000000. - ERROR: Write: 0x03020100 07060504 - ERROR: Read: 0x00000000 00000000 - ERROR: (0 bytes of RAM have been checked successfully) - ERROR: Failed to program targetDisconnecting ... - Disconnected请问这是什么问题？怎么解决？