Archer C20i: flash corruption

Hi,

My company has over 1000 units of Archer-C20i running on openwrt 15.05.

We have noticed a problem provoking bricking of the device that happened on ~40 of our units so far: flash gets corrupted and the device refuses to start. Openwrt stops at preinit, and does not even start network. We get continuously these messages at boot and later (from UART)

[ 7569.030000] jffs2: warning: (624) jffs2_get_inode_nodes: Eep. No valid nodes for ino #103.
[ 7569.040000] jffs2: warning: (624) jffs2_do_read_inode_internal: no data nodes found for ino #103
[ 7569.050000] jffs2: iget() failed for ino #103

We have made a dump of the flash and when binwalking into it we get:

DECIMAL       HEXADECIMAL     DESCRIPTION
--------------------------------------------------------------------------------
0             0x0             Squashfs filesystem, little endian, version 4.0, compression:lzma (non-standard type definition), size: 5536484 bytes,  2028 inodes, blocksize: 262144 bytes, created: Tue Apr 10 10:29:51 2018
5570560       0x550000        JFFS2 filesystem, little endian
5634291       0x55F8F3        LZMA compressed data, properties: 0x5D, dictionary size: 16777216 bytes, missing uncompressed size
5634340       0x55F924        LZMA compressed data, properties: 0x5D, dictionary size: 33554432 bytes, missing uncompressed size
5819545       0x58CC99        LZMA compressed data, properties: 0x5D, dictionary size: 33554432 bytes, missing uncompressed size
5819563       0x58CCAB        LZMA compressed data, properties: 0x5D, dictionary size: 33554432 bytes, missing uncompressed size
5823655       0x58DCA7        LZMA compressed data, properties: 0x5D, dictionary size: 33554432 bytes, missing uncompressed size
5823673       0x58DCB9        LZMA compressed data, properties: 0x5D, dictionary size: 33554432 bytes, missing uncompressed size
5829635       0x58F403        LZMA compressed data, properties: 0x5D, dictionary size: 33554432 bytes, missing uncompressed size
5829653       0x58F415        LZMA compressed data, properties: 0x5D, dictionary size: 33554432 bytes, missing uncompressed size
6352604       0x60EEDC        LZMA compressed data, properties: 0x5D, dictionary size: 33554432 bytes, missing uncompressed size
6352622       0x60EEEE        LZMA compressed data, properties: 0x5D, dictionary size: 33554432 bytes, missing uncompressed size
6356714       0x60FEEA        LZMA compressed data, properties: 0x5D, dictionary size: 33554432 bytes, missing uncompressed size
6356732       0x60FEFC        LZMA compressed data, properties: 0x5D, dictionary size: 33554432 bytes, missing uncompressed size
6607261       0x64D19D        mcrypt 2.2 encrypted data, algorithm: blowfish-448, mode: CBC, keymode: 8bit
6612624       0x64E690        LZMA compressed data, properties: 0x5D, dictionary size: 33554432 bytes, missing uncompressed size
6612642       0x64E6A2        LZMA compressed data, properties: 0x5D, dictionary size: 33554432 bytes, missing uncompressed size
6619136       0x650000        JFFS2 filesystem, little endian
6673473       0x65D441        LZMA compressed data, properties: 0x5D, dictionary size: 33554432 bytes, missing uncompressed size
6673491       0x65D453        LZMA compressed data, properties: 0x5D, dictionary size: 33554432 bytes, missing uncompressed size
6677171       0x65E2B3        LZMA compressed data, properties: 0x64, dictionary size: 65536 bytes, uncompressed size: 2686976 bytes
6678518       0x65E7F6        LZMA compressed data, properties: 0x5D, dictionary size: 33554432 bytes, missing uncompressed size
6678536       0x65E808        LZMA compressed data, properties: 0x5D, dictionary size: 33554432 bytes, missing uncompressed size

Reflashing the device or reseting the overlay partition allows the device to work again, but it can only be done form UART or TFTP.

We are not sure if it is a hardware problem or software problem, but we wanted to report it. It seems that this problem is correlated to high temperatures in the summer, although we will collect more data in the following weeks to make sure the correlation is significant.

Have you considered at least upgrading the the re-flashed units with 18.06 release. And working through the rest later.

https://openwrt.org/toh/hwdata/tp-link/tp-link_archer_c20i_ac750_v1

We may upgrade at some point, although last time we made some tests, newer kernel was reducing significantly throughput due to higher CPU consumption and higher Ram consumption, so we did not do it.

1 Like

Maybe VRM power circuits or capacitors issue. Try check hardware.