JavaCard OS

I am trying to import a key into a MUSCLE card.
The operationg procedures are as follows:

1- Upload and install the muscle applet

2- Initialize the applet

3- Verify the pin

4- Create the object with id (FF FF FF FE):
>>B0 5A 00 00 0E FF FF FF FE 00 00 00 44 00 00 00 00 00 00 00
<<90 00

5- Write into the object
>> B0 54 00 00 8D FF FF FF FE 00 00 00 00 84 00 01 00 80 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
<< 90 00

6- Import key
>> B0 32 04 00 07 00 00 FF FF 00 00 00 00
<< 6F 00

When I import a key into the card, it returns 6F 00. I don't know why this happened.
Could anybody provide a solution for me?

7 bytes seems to be a bit high for importing a key. The ACL in the data block is only six bytes. So modify it and try again.

Can you give us the commands to install the applet, applet initialization, pin verify?
And we can have the same environment to run this applet.

I guess the persistent memory space of your card is not enough, you can get the persistent memory size before you send the IMPORT KEY command.

Debug the applet, where the exception occured?