Help with writing to micro SD card

[Larry Finger]

I am helping to get wifi and Bluetooth woring under Linux using a Winbook TW100 
tablet. The main goal is working quite well; however, I am only able to run 
using Live media. Whenever I try to load Linux onto either the internal SD card, 
or one mounted in the external slot, the process stalls with nothing logged.

I know the external card is OK as I can read or write it when it is mounted in 
my laptop.

When I received the tablet, I used dd to back up the internal card. When I used 
a block size of 4M in that operation, it also froze; however, the standard block 
size (512) worked. That suggests that the standard Linux r/w operations on the 
device are too fast.

What should I do to get some debug information? If my idea is correct, how might 
I slow down the I/O to the device?

Thanks,

Larry
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