Just acquired two 850's for a back-to-back T1. One RCU already has TDM firmware on it, but the other has ATM C.01.18. Even though I factory reset it via dip switch, when the TFTP transfer completes (A04.04.71), there is a 'CHKSUM Failure'. I tried redownloading. Does the RCU need to be downgraded, or replaced? Is there a migration path? Both RCU's are 3rd gen.
The V35 led stays lit no matter what. I was able to upgrade to C0290, and then to C040471, which finally made the V35 led turn off. 'C' is for ADPCM Gen1 RCU's. I tried to flash A040471 at this point; no go. So far, any attempt to put a Gen3 file on this 1200376L1 card results in a CHKSUM failure.
I was able to load A.03.22 Gen1 TDM; this is the first 'A' that worked. Now it's stuck in a boot loop.
Nevermind. Upon further inspection, the screws that hold the daughterboard on are missing. I think someone put two different gen's together and pawned it off on somebody else.
Bricked, and trashed. Moving on...
I have replaced the RCU. The PN is 1200376L1. Is this not a 3rd Gen card? Once booted, I see A.03.57. Attempt to load A04.04.71 (3A040471). CHKSUM Failure! Attempt to load A04.04.71 (1A040471). Success! Same story on unit two's RCU.
Can anyone educate me as to why a 3rd gen card would only accept 1st gen firmware?
Part Number 1200376L1 is a 1st Gen. RCU. The 3rd Gen. RCU is PN: 1203376L1 (1203 instead of 1200).
So for the 1st Gen. RCU, the 1A040471.bin file is the correct FW. If you have any 3rd Gen. RCUs (1203376L1) then you should use the 3A040471.bin FW file.
Hope this helps,