Partition the SD Card

Nitrokeys
1

Currently the SD arrived with a FDISK Partion Table and 4 partitions:
[ul]]MBR/:m]
]fill to align to 2k sector/:m]
]4190209 sectors for MBR Partition (FAT32) which is not encrypted - which is around the 2.1 GB shown when the stick is connected/:m]
]22727680 sectors free ( which I assume to be the encrypted section ) - which is around 10.8 GB only/:m][/ul]

So I wonder:
Is Nitrokey Storage using a normal FDISK Table ? Or just code it as FDISK to be recognizable ?
What kind of file systems are supported ? On macOS Sierra, there is no FAT32 ( only exFAT ~which might be similar , but not recognized as such)
The current table doesn’t show the full capacity of the SD Card. Can I use a standard SD card inside Nitro Stick ?
Is there any hint/documentation (beside the source code :slight_smile: ) to find out how the SD card is formatted ?

Any help is appreciated as I still struggle with the portions and hidden volumes. I also want to give the encrypted partition more room and so wonder, if I could re-format/partition the SD card different with a smaller size for the standard functions

[Update]
I found the following in your source file git://nitrokey-storage-firmware/src/CON … _mmc_mci.h

#define SD_SIZE_UNCRYPTED_PARITION (1024*2*2048) // SD Blocks a 512 Bytes = 2048 MB #define SD_MAGIC_NUMBER_HIDDEN_CRYPTED_PARITION 0x23636923 // u32 for secure #define SD_START_HIDDEN_CRYPTED_PARITION (1024*2*1024) // SD Blocks a 512 Bytes = 2048 MB
Do I need to assume that you have hard-coded the partitions ? :open_mouth:

2

You can freely delete and change partitions as you like. The firmware doesn’t know any partitons. The allocation between unencrypted and encrypted area (which you referred to) are hardcoded and can’t be configured.

3

Thanks for the clarification.

Can I assume : I could create a new firmware with a different SD_SIZE_UNCRYPTED_PARITION value to shrink the unencrypted partition ?

4

Yes.