proxmark3 read write mifare ultralight card

E:\tech\proxmark3\ProxSpace\firmware-20150321>proxmark3 COM28
proxmark3> hf 14a reader
ATQA : 00 44
 UID : 00 00 00 00 00 00 00
 SAK : 00 [2]
MANUFACTURER : no tag-info available
TYPE : NXP MIFARE Ultralight | Ultralight C
SAK incorrectly claims that card doesn't support RATS
 ATS : 0a 78 00 81 02 db a0 c1 19 40 2a b5
       -  TL : length is 10 bytes
       -  T0 : TA1 is present, TB1 is present, TC1 is present, FSCI is 8 (FSC =
256)
       - TA1 : different divisors are supported, DR: [], DS: []
       - TB1 : SFGI = 1 (SFGT = 8192/fc), FWI = 8 (FWT = 1048576/fc)
       - TC1 : NAD is NOT supported, CID is supported
       -  HB : db a0 c1 19 40
Answers to chinese magic backdoor commands: NO
proxmark3>
proxmark3> hf mfu rdbl 0
--block no:0x00 (0)
isOk: 01
Data: 00 00 00 00
proxmark3> hf mfu rdbl 4
--block no:0x04 (4)
isOk: 01
Data: 00 00 00 00
proxmark3> hf mfu wrbl 4 ffffffff
--block no:04
--data: ff ff ff ff
#db# WRITE BLOCK FINISHED
isOk:01
proxmark3> hf mfu rdbl 4
--block no:0x04 (4)
isOk: 01
Data: ff ff ff ff
proxmark3>

http://www.xfpga.com/html_products/proxmark3-20.html

http://www.xfpga.com/html_products/UID-changeable-mifare-ultralight-card-en-95.html