The LM computer on Apollo 14 had to be updated in flight in order to bypass a faulty abort switch.[1] The patch was applied by radioing the instructions to the crew and having them enter it manually.
Note that this was not a code patch: This was a sequence of changes to the program state that tricked it into ignoring the abort switch. The code itself was stored in read only core rope memory, so it was physically impossible to change it (the memory was written by appropriately winding wires around ferrite cores).
The LM computer on Apollo 14 had to be updated in flight in order to bypass a faulty abort switch.[1] The patch was applied by radioing the instructions to the crew and having them enter it manually.
[1] https://www.hq.nasa.gov/alsj/a11/a11.1201-pa.html