Login is pi/raspberry
the problem with the log is that it displays the board drops and init of the boards but its completely random.
Sometimes it doesn't even gets it to bring the board back up again.
This happens on multi-pools . not so much on the litecoinpool.
Diagnostics look like problems in the driver or on the spi bus.
The driver is compiled with cgminer so if we do not have hands on the source code its hard to solve this without innosilicon.
Greets,
Nowayz
Edit:
Add log from cgminer with faults for those who want to see

These are on nicehash with batch 2 and version 2 software
[2016-11-07 17:52:33] Started cgminer 3.9.0
[2016-11-07 17:52:33] Run Reset=1
[2016-11-07 17:52:33] ST MCU hardware reset start
[2016-11-07 17:52:37] SPI Speed 4000 kHz
[2016-11-07 17:52:37] ST MCU - Enable (Pre-header)
[2016-11-07 17:52:37] Run temperature 35C
[2016-11-07 17:52:37] A1 = 1200,7
[2016-11-07 17:52:37] A1 PLL Clock = 1200MHz
[2016-11-07 17:52:37] A1 = 1200,7
[2016-11-07 17:52:37] A1 PLL Clock = 1200MHz
[2016-11-07 17:52:37] A1 = 1200,7
[2016-11-07 17:52:37] A1 PLL Clock = 1200MHz
[2016-11-07 17:52:37] A1 = 1200,7
[2016-11-07 17:52:37] A1 PLL Clock = 1200MHz
[2016-11-07 17:52:37] A1 = 1200,7
[2016-11-07 17:52:37] A1 PLL Clock = 1200MHz
[2016-11-07 17:52:37] A1 = 1200,7
[2016-11-07 17:52:37] A1 PLL Clock = 1200MHz
[2016-11-07 17:52:37] AUTO GPIO CS
[2016-11-07 17:52:37] Failure(cs0)(2): missing ACK for cmd 0x02
[2016-11-07 17:52:37] ACK(cs0) timeout:cmd_POWER_ON_BCAST-0.0625s
[2016-11-07 17:52:40] Failure(cs0)(2): missing ACK for cmd 0x04
[2016-11-07 17:52:40] ACK(cs0) timeout:cmd_RESET_BCAST - 0.61 ms
[2016-11-07 17:52:40] Failure(cs1)(2): missing ACK for cmd 0x02
[2016-11-07 17:52:40] ACK(cs1) timeout:cmd_POWER_ON_BCAST-0.0573s
[2016-11-07 17:52:43] Failure(cs1)(2): missing ACK for cmd 0x04
[2016-11-07 17:52:43] ACK(cs1) timeout:cmd_RESET_BCAST - 0.65 ms
[2016-11-07 17:52:43] spidev0.0(cs2): Found 20 A2 chips
[2016-11-07 17:52:43] Found chip 1 with 100 active cores
[2016-11-07 17:52:43] Found chip 2 with 100 active cores
[2016-11-07 17:52:43] Found chip 3 with 100 active cores
[2016-11-07 17:52:43] Found chip 4 with 100 active cores
[2016-11-07 17:52:43] Found chip 5 with 100 active cores
[2016-11-07 17:52:43] Found chip 6 with 100 active cores
[2016-11-07 17:52:43] Found chip 7 with 100 active cores
[2016-11-07 17:52:43] Found chip 8 with 100 active cores
[2016-11-07 17:52:43] Found chip 9 with 100 active cores
[2016-11-07 17:52:43] Found chip 10 with 100 active cores
[2016-11-07 17:52:43] Found chip 11 with 100 active cores
[2016-11-07 17:52:43] Found chip 12 with 100 active cores
[2016-11-07 17:52:43] Found chip 13 with 100 active cores
[2016-11-07 17:52:43] Found chip 14 with 100 active cores
[2016-11-07 17:52:43] Found chip 15 with 100 active cores
[2016-11-07 17:52:43] Found chip 16 with 100 active cores
[2016-11-07 17:52:43] Found chip 17 with 100 active cores
[2016-11-07 17:52:43] Found chip 18 with 100 active cores
[2016-11-07 17:52:43] Found chip 19 with 100 active cores
[2016-11-07 17:52:43] Found chip 20 with 100 active cores
[2016-11-07 17:52:43] Found 20 chips with total 2000 active cores
[2016-11-07 17:52:43] PI(cs5) match the cg and dr
[2016-11-07 17:52:43] SPI(cs2) A1_SetA1Vol
[2016-11-07 17:52:46] spidev0.0(cs3): Found 20 A2 chips
[2016-11-07 17:52:46] Found chip 1 with 100 active cores
[2016-11-07 17:52:46] Found chip 2 with 100 active cores
[2016-11-07 17:52:46] Found chip 3 with 100 active cores
[2016-11-07 17:52:46] Found chip 4 with 100 active cores
[2016-11-07 17:52:46] Found chip 5 with 100 active cores
[2016-11-07 17:52:46] Found chip 6 with 100 active cores
[2016-11-07 17:52:46] Found chip 7 with 100 active cores
[2016-11-07 17:52:46] Found chip 8 with 100 active cores
[2016-11-07 17:52:46] Found chip 9 with 100 active cores
[2016-11-07 17:52:46] Found chip 10 with 100 active cores
[2016-11-07 17:52:46] Found chip 11 with 100 active cores
[2016-11-07 17:52:46] Found chip 12 with 100 active cores
[2016-11-07 17:52:46] Found chip 13 with 100 active cores
[2016-11-07 17:52:46] Found chip 14 with 100 active cores
[2016-11-07 17:52:46] Found chip 15 with 100 active cores
[2016-11-07 17:52:46] Found chip 16 with 100 active cores
[2016-11-07 17:52:46] Found chip 17 with 100 active cores
[2016-11-07 17:52:46] Found chip 18 with 100 active cores
[2016-11-07 17:52:46] Found chip 19 with 100 active cores
[2016-11-07 17:52:46] Found chip 20 with 100 active cores
[2016-11-07 17:52:46] Found 20 chips with total 2000 active cores
[2016-11-07 17:52:46] PI(cs5) match the cg and dr
[2016-11-07 17:52:46] SPI(cs3) A1_SetA1Vol
[2016-11-07 17:52:49] spidev0.0(cs4): Found 20 A2 chips
[2016-11-07 17:52:49] Found chip 1 with 98 active cores
[2016-11-07 17:52:49] Found chip 2 with 99 active cores
[2016-11-07 17:52:49] Found chip 3 with 99 active cores
[2016-11-07 17:52:49] Found chip 4 with 99 active cores
[2016-11-07 17:52:49] Found chip 5 with 99 active cores
[2016-11-07 17:52:49] Found chip 6 with 94 active cores
[2016-11-07 17:52:49] Found chip 7 with 99 active cores
[2016-11-07 17:52:49] Found chip 8 with 97 active cores
[2016-11-07 17:52:49] Found chip 9 with 98 active cores
[2016-11-07 17:52:49] Found chip 10 with 99 active cores
[2016-11-07 17:52:49] Found chip 11 with 99 active cores
[2016-11-07 17:52:49] Found chip 12 with 98 active cores
[2016-11-07 17:52:49] Found chip 13 with 98 active cores
[2016-11-07 17:52:49] Found chip 14 with 99 active cores
[2016-11-07 17:52:49] Found chip 15 with 99 active cores
[2016-11-07 17:52:49] Found chip 16 with 95 active cores
[2016-11-07 17:52:49] Found chip 17 with 99 active cores
[2016-11-07 17:52:49] Found chip 18 with 99 active cores
[2016-11-07 17:52:49] Found chip 19 with 99 active cores
[2016-11-07 17:52:49] Found chip 20 with 96 active cores
[2016-11-07 17:52:49] Found 20 chips with total 1962 active cores
[2016-11-07 17:52:49] PI(cs5) match the cg and dr
[2016-11-07 17:52:50] SPI(cs4) A1_SetA1Vol
[2016-11-07 17:52:50] Failure(cs5)(2): missing ACK for cmd 0x02
[2016-11-07 17:52:50] ACK(cs5) timeout:cmd_POWER_ON_BCAST-0.0548s
[2016-11-07 17:52:53] Failure(cs5)(2): missing ACK for cmd 0x04
[2016-11-07 17:52:53] ACK(cs5) timeout:cmd_RESET_BCAST - 0.71 ms
[2016-11-07 17:52:53] A2 boards=3, active cores=5962, speed=427.12M
[2016-11-07 17:52:53] Tan total_devices : 3
[2016-11-07 17:52:53] Tan cs_cnt_error
after some time cs2 drops and comes back ..
[2016-11-07 17:56:17] spidev0.0(cs2): Found 20 A2 chips
[2016-11-07 17:56:17] Found chip 1 with 100 active cores
[2016-11-07 17:56:17] Found chip 2 with 100 active cores
[2016-11-07 17:56:17] Found chip 3 with 100 active cores
[2016-11-07 17:56:17] Found chip 4 with 100 active cores
[2016-11-07 17:56:17] Found chip 5 with 100 active cores
[2016-11-07 17:56:17] Found chip 6 with 100 active cores
[2016-11-07 17:56:17] Found chip 7 with 100 active cores
[2016-11-07 17:56:17] Found chip 8 with 100 active cores
[2016-11-07 17:56:17] Found chip 9 with 100 active cores
[2016-11-07 17:56:17] Found chip 10 with 100 active cores
[2016-11-07 17:56:17] Found chip 11 with 100 active cores
[2016-11-07 17:56:17] Found chip 12 with 100 active cores
[2016-11-07 17:56:17] Found chip 13 with 100 active cores
[2016-11-07 17:56:17] Found chip 14 with 100 active cores
[2016-11-07 17:56:17] Found chip 15 with 100 active cores
[2016-11-07 17:56:17] Found chip 16 with 100 active cores
[2016-11-07 17:56:17] Found chip 17 with 100 active cores
[2016-11-07 17:56:17] Found chip 18 with 100 active cores
[2016-11-07 17:56:17] Found chip 19 with 100 active cores
[2016-11-07 17:56:17] Found chip 20 with 100 active cores
[2016-11-07 17:56:17] Found 20 chips with total 2000 active cores
[2016-11-07 17:56:18] Accepted 0880d755 Diff 7.71K/4096 BA2 2 pool 0
[2016-11-07 17:56:18] Accepted 0880d755 Diff 7.71K/4096 BA2 2
[2016-11-07 17:56:18] Accepted 01f39c93 Diff 33.6K/4096 BA2 1 pool 0
[2016-11-07 17:56:18] Accepted 01f39c93 Diff 33.6K/4096 BA2 1
[2016-11-07 17:56:18] chip(cs3) 14: invalid nonce 0x0e12ca00
[2016-11-07 17:56:20] chip(cs2) 10: invalid nonce 0x41f71900
(5s):182.1M (avg):200.0Mh/s | A:626688 R:0 WU:180472.5/m
And cs3 drops and comes back
[2016-11-07 17:57:40] Reinit board (cs3)
[2016-11-07 17:57:40] spidev0.0(cs3): Found 20 A2 chips
[2016-11-07 17:57:40] Found chip 1 with 100 active cores
[2016-11-07 17:57:40] Found chip 2 with 100 active cores
[2016-11-07 17:57:40] Found chip 3 with 100 active cores
[2016-11-07 17:57:40] Found chip 4 with 100 active cores
[2016-11-07 17:57:40] Found chip 5 with 100 active cores
[2016-11-07 17:57:40] Found chip 6 with 100 active cores
[2016-11-07 17:57:40] Found chip 7 with 100 active cores
[2016-11-07 17:57:40] Found chip 8 with 100 active cores
[2016-11-07 17:57:40] Found chip 9 with 100 active cores
[2016-11-07 17:57:40] Found chip 10 with 100 active cores
[2016-11-07 17:57:40] Found chip 11 with 100 active cores
[2016-11-07 17:57:40] Found chip 12 with 100 active cores
[2016-11-07 17:57:40] Found chip 13 with 100 active cores
[2016-11-07 17:57:40] Found chip 14 with 100 active cores
[2016-11-07 17:57:40] Found chip 15 with 100 active cores
[2016-11-07 17:57:40] Found chip 16 with 100 active cores
[2016-11-07 17:57:40] Found chip 17 with 100 active cores
[2016-11-07 17:57:40] Found chip 18 with 100 active cores
[2016-11-07 17:57:40] Found chip 19 with 100 active cores
[2016-11-07 17:57:40] Found chip 20 with 100 active cores
[2016-11-07 17:57:40] Found 20 chips with total 2000 active cores
[2016-11-07 17:57:43] Accepted 0e258aec Diff 4.63K/4096 BA2 2 pool 0
[2016-11-07 17:57:43] Accepted 0e258aec Diff 4.63K/4096 BA2 2
(5s):192.2M (avg):200.0Mh/s | A:864256 R:0 WU:179076.9/m
And cs4 comes back but other board has dropped
[2016-11-07 17:58:36] spidev0.0(cs4): Found 20 A2 chips
[2016-11-07 17:58:36] Found chip 1 with 98 active cores
[2016-11-07 17:58:36] Found chip 2 with 99 active cores
[2016-11-07 17:58:36] Found chip 3 with 99 active cores
[2016-11-07 17:58:36] Found chip 4 with 99 active cores
[2016-11-07 17:58:36] Found chip 5 with 99 active cores
[2016-11-07 17:58:36] Found chip 6 with 94 active cores
[2016-11-07 17:58:36] Found chip 7 with 99 active cores
[2016-11-07 17:58:36] Found chip 8 with 97 active cores
[2016-11-07 17:58:36] Found chip 9 with 98 active cores
[2016-11-07 17:58:36] Found chip 10 with 99 active cores
[2016-11-07 17:58:36] Found chip 11 with 99 active cores
[2016-11-07 17:58:36] Found chip 12 with 98 active cores
[2016-11-07 17:58:36] Found chip 13 with 98 active cores
[2016-11-07 17:58:36] Found chip 14 with 99 active cores
[2016-11-07 17:58:36] Found chip 15 with 99 active cores
[2016-11-07 17:58:36] Found chip 16 with 95 active cores
[2016-11-07 17:58:36] Found chip 17 with 99 active cores
[2016-11-07 17:58:36] Found chip 18 with 99 active cores
[2016-11-07 17:58:36] Found chip 19 with 99 active cores
[2016-11-07 17:58:36] Found chip 20 with 96 active cores
[2016-11-07 17:58:36] Found 20 chips with total 1962 active cores
[2016-11-07 17:58:38] chip(cs2) 4: invalid nonce 0xa3b1e700
[2016-11-07 17:58:38] Accepted 031d35c4 Diff 21K/8192 BA2 0 pool 0
[2016-11-07 17:58:38] Accepted 031d35c4 Diff 21K/8192 BA2 0
[2016-11-07 17:58:39] Accepted a932e209 Diff 99.2K/8192 BA2 1 pool 0
[2016-11-07 17:58:39] Accepted a932e209 Diff 99.2K/8192 BA2 1
(5s):166.0M (avg):197.9Mh/s | A:1101824 R:0 WU:191204.7/m