220-1101 Mobile Devices Practice Question
A user reports that their smartphone battery percentage jumps erratically—for example, showing 50% then suddenly dropping to 10% and shutting down. The technician verifies the battery is not swollen, the charging port is clean, and the device charges normally. Which of the following should the technician try NEXT?
⚠ Common exam trap
CompTIA often tests the distinction between hardware failure symptoms (swelling, no charge) and software/firmware calibration issues, leading candidates to prematurely replace the battery instead of attempting a non-destructive calibration first.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Calibrate the battery
The erratic battery percentage drop without physical swelling or charging issues indicates a software calibration problem, not a hardware failure. Calibrating the battery resets the fuel gauge chip's learned capacity values, allowing the operating system to accurately report charge levels. This is the correct next step before replacing the battery.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Replace the battery
Why it's wrong here
Battery replacement is the final remedy, not the first step, when erratic percentage jumps occur without physical signs like swelling or leakage. Replacing a healthy battery wastes components and cost, and the true issue is often a miscalibrated fuel gauge, which calibration can correct. Only if a full calibration cycle fails to stabilize readings, or hardware diagnostics show elevated internal resistance or capacity loss, should a battery swap be considered.
- ✗
Update firmware
Why it's wrong here
Updating firmware addresses low-level bugs in the device’s operating system or hardware abstraction layer, but the symptom of erratic battery percentage jumps with normal charging and no swelling points to a degraded or failing battery cell whose internal impedance has risen, causing voltage sag under load—a hardware fault no firmware patch can correct. It is tempting because firmware updates often resolve phantom battery reporting issues caused by calibration errors or OS glitches, and would be correct if the battery were healthy but the charge controller misread capacity due to a software bug.
- ✓
Calibrate the battery
Why this is correct
Calibration realigns the fuel gauge's state-of-charge calculation with the battery's actual voltage, which lithium-ion cells report nonlinearly. A full discharge to 0% and an uninterrupted charge to 100% teaches the charge controller the true empty and full thresholds, correcting the drift that causes erratic jumps. This is the correct first step because the charging hardware is verified working and the symptom pattern—normal charging but erratic reporting—points squarely to a software-side misread, not a physical defect.
- ✗
Replace the charging port
Why it's wrong here
A functional charging port is confirmed by consistent power delivery and no physical damage, so replacing it cannot address a software-level fuel-gauge miscalibration. Faulty ports typically produce intermittent charging, loose fit, or no connection at all, not stable charging with erratic percentage readouts. Removing a working port introduces unnecessary risk of damage and fails to target the actual cause, which is the calibration between battery and charge controller.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 220-1101 practice question is part of Courseiva's free CompTIA certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the 220-1101 exam.