This is just a short update, during upgrading SAP, SUM will switch to <sid>adm and set up its own environment variables to call brtools or kernel executable.
To narrow down this issue, we can do as followings:
1. Call the same command from OS level, if the same error occurs, then it means the problem has nothing to do with SUM, we need to focus on from OS level directly
2. If OS calls is successful (this is often the case), then we need to review the SUM log to see how the command was called. Normally need to find out which environment variables are set, then reproduce this issue from OS level. By doing this we can roughly understand, the problem is related to environment variable combination between SUM's and OS's. Then we need to check the error, review the environment variable case by case.
FYI, SUM will set ORACLE_HOME to .../tmp, this "wrongly" set is on purpose, don't try to solve any issue by changing ORACLE_HOME to "correct" one.