Durnig the replacement of a RPU in a NE20E equipment, after modifying the boot parameters (saved-configuration, system-software, paf.txt and license.txt) and reboot the RPU (on-site), the new RPU couldn't register and was continuously reseting.
After several test we verified the paf.txt and license.txt files. We found something very particular; The running version in the main RPU was V200R005C03B383, but the paf.txt and license.txt files were for version V200R005C03B581.
In this situation, the NE20E can works properly with only one RPU, if you try to install a new RPU in version V200R005C03B383, the new RPU continuously reset.
The problem is the syncrhonization process between both RPUs, as there is a mismatch between the license.txt and paf.txt and the software version, the RPU can't register.
This is the error we can see in the device:
Sep 16 2009 08:57:01 XXXXXXXXXXXX %%01SRM/3/LVDSERR(l): Lvds Error!
Sep 16 2009 08:57:09 XXXXXXXXXXXX %%01SRM/4/SLAVERPUINFOSWAPOK(l): RPU&NPU hardware present information swapped ok.
Copy the apropiate paf.txt and license.txt files to the RPU and everything works properly.
When you are installing a new RPU in a NE20E it is recommended to review the version of the license.txt and paf.txt files even if you are copying these files from the master RPU.