QSPI Flash stopped working

Official Hardware Mega GIGA R1 WiFi
1

I was using the QSPI Flash for a while now - storing Config Data for my Application in it. Using the KVStore/** API - all worked great and flawless until yesterday when in the middle of updating a Setting the Giga "froze". After a reset I get an error and the 4 slot/4 fast blinking red of a crashed mbed core.
all the function work as before including the on Chip Flash.
Here are the steps I already took to see if I can get around the problem and resurrect it:

  1. Used the QSPIformat tool from examples to reformat the QSPI Flash -> format worked but KV still ha the same problem...
  2. Tried different partition schemes -> No luck either
  3. Used dfu to put boot loader back on. -> No luck
  4. Tried format again after the bootloader step from above.
  5. Tried to use the test program "Programming the QSPI Flash" found in the documentation. -> No Luck

Snippet of Code from step 5
It seems that creating the root object is successful

// Create a block device on the available space of the flash
   QSPIFBlockDevice root(PD_11, PD_12, PF_7, PD_13, PF_10, PG_6, QSPIF_POLARITY_MODE_1, 40000000);
ret = root.init();

Since return code is 0
But the next step creating the block device fails

// Create the Blockdevice
MBRBlockDevice blockDevice(&root, 1);
ret = blockDevice.init();

With return code : -3101 AFAIK this is a somewhat catchall and points to an underlying HW or Partition problem.

So anyone have an idea on how the further troubleshoot it and get to the root cause or Question for Arduino support does this mean my QSPI Flash is broken ?