TL-MR3020. ping works telnet doesn't

Hi,

i try to restore to the original firmware (mr3020nv1_en_3_17_2_up_boot(140610)) and end up with:

Writing from xxxxx.bin to firmware ... [e]Failed to erase block

after that ... ping works, telnet doesn't.
(control panel > network and internet > network connections > ethernet > "network cable unplugged")

what i have to do to revert to the original firmware?
or re-install piratebox?

thanks in advance

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i follow these instructions:

Restoring your MR3020 Piratebox back to original firmware using TP-Link MR3020 hardware
Version 1-5-11-2012
Chaka Hamilton
chakahamilton@gmail.com
or PM on the piratebox Forum: Pabell


STEP 7.

At the # type the following command:

mtd -r write tplink.bin firmware

Press Enter

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[RESULTS]

root@piratebox:~# cd /tmp

root@piratebox:/tmp# mtd -r write tplink.bin firmware

Unlocking firmware ...

Writing from tplink.bin to firmware ... [e]Failed to erase block

root@piratebox:/tmp#

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[wiki.openwrt.org]

Failsafe Mode

• Set your computer's IP to 192.168.1.2, subnet 255.255.255.0
• Connect the TL-MR3020 to your computer via ethernet
• Power on the TL-MR3020
• When the WPS button starts to blink:
• on BB (Breaking Barrier / trunk) move the sliding switch quickly from one side to the other.

• Do this until the WPS button starts blinking faster.
• The device is now in Failsafe-Mode
• You may access it by using telnet 192.168.1.1