After formatting one of the cards with SDFormatter v3.1 and running the tests again, here are the results:
:::::::::::::::: Bench :::::::::::::::::::::
Free RAM: 7301
Type is FAT16
error: open failed
SD errorCode: 0X13
::::::::::::: QuickStart :::::::::::::::::::
SD chip select is the key hardware option.
Common values are:
Arduino Ethernet shield, pin 4
Sparkfun SD shield, pin 8
Adafruit SD shields and modules, pin 10
Enter the chip select pin number: 20
Card successfully initialized.
Card size: 2055 MB (MB = 1,000,000 bytes)
Volume is FAT16, Cluster size (bytes): 32768
Files found (name date time size):
BENCH.DAT 2000-01-01 01:00:00 0
Success! Type any character to restart.
:::::::::::::::::: SdInfo :::::::::::::::::
type any character to start
init time: 4 ms
Card type: SD2
Manufacturer ID: 0X0
OEM ID:
Product: APPSD
Version: 3.0
Serial number: 2290649224
Manufacturing date: 10/2010
cardSize: 4014080 (512 byte blocks)
flashEraseSize: 128 blocks
eraseSingleBlock: true
SD Partition Table
part,boot,type,start,length
1,0X0,0X6,245,4011595
2,0X0,0X0,0,0
3,0X0,0X0,0,0
4,0X0,0X0,0,0
Volume is FAT16
blocksPerCluster: 64
clusterCount: 62673
freeClusters: 62673
fatStartBlock: 246
fatCount: 2
blocksPerFat: 245
rootDirStart: 736
dataStartBlock: 768