Forum Discussion
F5 BIG-IP i11000 stuck at B7 – cannot interrupt boot / ESC not working
- Jan 26, 2026
Hi Lucas, hope you're doing well. Regarding the issue that you're facing, I think it's best to open up a support case with F5. At the same time, you can perform some troubleshooting steps before opening a case with us.
According to KB K04158544: Determine possible cause of BIG-IP iSeries platform hardware failures (https://my.f5.com/manage/s/article/K04158544), when the serial console output shows rolling B7 and B9 codes, this indicates a memory failure.
Specific Symptoms for Memory Failure:
- Serial console output: Rolling B7 and B9 codes
- Serial console log: Contains strings with B7 and B9
Example pattern from the KB:
19A1A3A3A3A3A3A3A7A9AAAAABACADAFB0B1AF19A1A3A3A3A3A3A3A7A9AAA7A7A7A7A8A9A9A9A9AAAAAEAFB0B1B4B2B3B6B7B7B7B7B7B7B7B7B7B7B7B7B7B7B7B7B7B7B7B7B7B7B7B7B7B7B7B8B9BAB7BF
Additional Context from KB K65073734:
KB K65073734: BIG-IP not booting/responding (https://my.f5.com/manage/s/article/K65073734) specifically addresses your exact symptoms:
- Description: BIG-IP appliance not booting up, console output gets stuck at B7 Hex code after power cycle, no errors on LCD
- Cause: Unknown at time of publication
- Recommended Actions: The unit might need hardware replacement. Open a case with F5 support for confirmation.
Troubleshooting Steps (Before RMA)
Based on similar cases, you should attempt these steps:
- Try accessing the AOM menu:
- Press Esc + Shift + 9 (or Esc + ( on US keyboard)
- If AOM menu appears, try:
- Press "I" to display platform information
- Press "P" to power off/on the host subsystem
- Run hidden diagnostic commands:
- Esc then type "pel" and press Enter
- Esc then type "diag" and press Enter
- Verify console settings:
- Baud rate: 19200
- Try different console cable/laptop to rule out connection issues
- Check if ESC key is working:
- The inability to interrupt boot suggests either console communication issues or severe hardware failure
Recommendation
Based on the evidence from KB articles and similar cases:
This is most likely a hardware failure (memory-related) that will require RMA (Return Merchandise Authorization).
Next Steps:
- If you haven't already, attempt the AOM menu access (Esc + Shift + 9)
- If AOM is accessible, collect the pel and diag logs
- Contact F5 Technical Support to open an RMA case
- Reference KB K04158544 and KB K65073734 when opening your support case
- Provide any console logs you've captured
The hardware failures documented in these KBs typically require replacement. For more information about the RMA process, refer to K12882: Overview of the F5 RMA process (https://my.f5.com/manage/s/article/K12882).
Let us know if the above steps do not work, and we can assist you to open up a case, or you can open the case via myF5.
Cheers,
Mo
Hi Lucas, hope you're doing well. Regarding the issue that you're facing, I think it's best to open up a support case with F5. At the same time, you can perform some troubleshooting steps before opening a case with us.
According to KB K04158544: Determine possible cause of BIG-IP iSeries platform hardware failures (https://my.f5.com/manage/s/article/K04158544), when the serial console output shows rolling B7 and B9 codes, this indicates a memory failure.
Specific Symptoms for Memory Failure:
- Serial console output: Rolling B7 and B9 codes
- Serial console log: Contains strings with B7 and B9
Example pattern from the KB:
19A1A3A3A3A3A3A3A7A9AAAAABACADAFB0B1AF19A1A3A3A3A3A3A3A7A9AAA7A7A7A7A8A9A9A9A9AAAAAEAFB0B1B4B2B3B6B7B7B7B7B7B7B7B7B7B7B7B7B7B7B7B7B7B7B7B7B7B7B7B7B7B7B7B8B9BAB7BF
Additional Context from KB K65073734:
KB K65073734: BIG-IP not booting/responding (https://my.f5.com/manage/s/article/K65073734) specifically addresses your exact symptoms:
- Description: BIG-IP appliance not booting up, console output gets stuck at B7 Hex code after power cycle, no errors on LCD
- Cause: Unknown at time of publication
- Recommended Actions: The unit might need hardware replacement. Open a case with F5 support for confirmation.
Troubleshooting Steps (Before RMA)
Based on similar cases, you should attempt these steps:
- Try accessing the AOM menu:
- Press Esc + Shift + 9 (or Esc + ( on US keyboard)
- If AOM menu appears, try:
- Press "I" to display platform information
- Press "P" to power off/on the host subsystem
- Run hidden diagnostic commands:
- Esc then type "pel" and press Enter
- Esc then type "diag" and press Enter
- Verify console settings:
- Baud rate: 19200
- Try different console cable/laptop to rule out connection issues
- Check if ESC key is working:
- The inability to interrupt boot suggests either console communication issues or severe hardware failure
Recommendation
Based on the evidence from KB articles and similar cases:
This is most likely a hardware failure (memory-related) that will require RMA (Return Merchandise Authorization).
Next Steps:
- If you haven't already, attempt the AOM menu access (Esc + Shift + 9)
- If AOM is accessible, collect the pel and diag logs
- Contact F5 Technical Support to open an RMA case
- Reference KB K04158544 and KB K65073734 when opening your support case
- Provide any console logs you've captured
The hardware failures documented in these KBs typically require replacement. For more information about the RMA process, refer to K12882: Overview of the F5 RMA process (https://my.f5.com/manage/s/article/K12882).
Let us know if the above steps do not work, and we can assist you to open up a case, or you can open the case via myF5.
Cheers,
Mo
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