Exact model-family answer directory

Samsung Galaxy S21 Ultra troubleshooting

Choose the symptom actually shown by SM-G998*. Current Galaxy family; confirm the complete SM identifier, region and One UI version before repair or firmware instructions. Error codes remain separate records because the same characters can mean different things on another platform.

battery drainnot chargingoverheatingWi-Fino serviceBluetooth

Reviewed records

18 exact answers

Not sure where the fault is?

Samsung · app crashing

Samsung Galaxy S21 Ultra app keeps crashing, freezing or will not open

For the Samsung Galaxy S21 Ultra, one app versus the operating system, storage and service state determines the safe sequence.

Open record Samsung · battery drain

Samsung Galaxy S21 Ultra battery drains too quickly

For the Samsung Galaxy S21 Ultra, recent update/indexing, screen/radio use, background activity, signal and battery condition should be measured before replacement.

Open record Samsung · biometric unlock

Samsung Galaxy S21 Ultra biometric unlock is not working

For the Samsung Galaxy S21 Ultra, sensor obstruction, enrolled appearance/finger, protector, environment and hardware should be separated.

Open record Samsung · camera blurry

Samsung Galaxy S21 Ultra camera is blurry, shakes or will not focus

For the Samsung Galaxy S21 Ultra, lens contamination, case magnets, one app/lens and camera hardware should be separated.

Open record Samsung · calls

Samsung Galaxy S21 Ultra cannot make calls or send messages

For the Samsung Galaxy S21 Ultra, carrier service, selected line, account activation, recipient-specific block and messaging service should be separated.

Open record Samsung · overheating

Samsung Galaxy S21 Ultra gets hot or shows a temperature warning

For the Samsung Galaxy S21 Ultra, high workload, charging, signal search, environment and a failing battery must be separated.

Open record Samsung · GPS

Samsung Galaxy S21 Ultra GPS or location is inaccurate

For the Samsung Galaxy S21 Ultra, app permission, precise-location setting, outdoor satellite view, network assistance and sensor calibration should be separated.

Open record Samsung · no service

Samsung Galaxy S21 Ultra has no cellular service or data

For the Samsung Galaxy S21 Ultra, carrier outage/account/provisioning, SIM/eSIM, coverage, line selection and device radio should be separated.

Open record Samsung · microphone

Samsung Galaxy S21 Ultra microphone is quiet, muffled or not working

For the Samsung Galaxy S21 Ultra, different apps and call modes use different microphones.

Open record Samsung · notifications

Samsung Galaxy S21 Ultra notifications are delayed or missing

For the Samsung Galaxy S21 Ultra, app permission, channel/category, Focus modes, background restriction, account sync and network should be separated.

Open record Samsung · not syncing

Samsung Galaxy S21 Ultra photos, contacts, messages or account data will not sync

For the Samsung Galaxy S21 Ultra, account status, cloud capacity, network, permissions and local storage should be separated before sign-out.

Open record Samsung · touchscreen

Samsung Galaxy S21 Ultra screen or touch input is not working correctly

For the Samsung Galaxy S21 Ultra, one app/region, moisture, protector/case, charger interference and display hardware should be separated.

Open record Samsung · update failed

Samsung Galaxy S21 Ultra software update will not download or install

For the Samsung Galaxy S21 Ultra, eligibility, power, storage, network, date/time and update service should be checked before recovery.

Open record Samsung · speaker

Samsung Galaxy S21 Ultra speaker is quiet, distorted or has no sound

For the Samsung Galaxy S21 Ultra, earpiece, loudspeaker, Bluetooth routing, app audio and obstruction should be separated.

Open record Samsung · storage full

Samsung Galaxy S21 Ultra storage is full or the device cannot install updates

For the Samsung Galaxy S21 Ultra, large media, downloads, app caches and system-update reserve should be measured before deletion.

Open record Samsung · not charging

Samsung Galaxy S21 Ultra will not charge or charges slowly

For the Samsung Galaxy S21 Ultra, power source, cable/adapter, port debris/liquid, temperature and battery protection should be separated.

Open record Samsung · Wi-Fi

Samsung Galaxy S21 Ultra will not connect to Wi-Fi or keeps disconnecting

For the Samsung Galaxy S21 Ultra, one network, all networks, VPN/profile and radio hardware produce different fixes.

Open record Samsung · Bluetooth

Samsung Galaxy S21 Ultra will not pair or stay connected over Bluetooth

For the Samsung Galaxy S21 Ultra, accessory pairing state, competing hosts, profile support and radio issues should be isolated.

Open record

Confirm the model first

Which units this covers, and how to tell yours is one of them

Every answer below is scoped to these model identifiers. A neighbouring model in the same line can use a different part, a different reset sequence or a different radio, so matching the identifier before following a procedure is the step that decides whether the rest of the page applies to you.

Model numbers and patterns: SM-G998*
What that covers: Current Galaxy family; confirm the complete SM identifier, region and One UI version before repair or firmware instructions.

Published specification

What is true of this model and changes how you fix it

These are the properties that decide which procedure applies. Each is read from the manufacturer’s own published figures for this model, not carried over from a sibling that shares its retail name.

Tier — flagship Ultra (S Pen support, NO slot): The S21 Ultra supports an S Pen but has NO built-in storage slot — you buy the S Pen and a case with a pen holder separately. This is different from the S22 Ultra onward, which integrate the pen. So 'where does the S Pen go' is: it does not store in the phone on this model.
One UI / Android: One UI over Android; nearing the end of its major-update window. DeX support.
eSIM + physical SIM, IP68: eSIM and physical SIM, IP68, fast + wireless charging.

Where these figures were read. samsung.com Galaxy S21 Ultra (flagship, S Pen supported but NO built-in slot), read 2026-09-01

Manufacturer support for this product line. Samsung Support — Mobile device support. Official Galaxy model manuals, diagnostics, updates and repair support.

Exact questions

Questions that only have an answer for the Samsung Galaxy S21 Ultra

Each answer below uses this model’s own published figures. The same question asked about a different model in the line has a different answer, which is why it is answered here rather than on a general page.

Where do I store the S Pen on my Galaxy S21 Ultra?+

You don't store it in the phone — the S21 Ultra supports an S Pen but, unlike the S22 Ultra and later, it has no built-in S Pen slot. Samsung sold a separate S Pen and a case with a pen loop for it. So there is no internal dock to charge it and the basic S Pen has no Bluetooth button features (the pricier S21 Ultra 'S Pen Pro' added those). Integrated, stored S Pens start with the S22 Ultra.

Structured depth, not empty permutations

Every published record carries a direct answer, scope, ordered fixes, risk notes and sources.

Device and manufacturer hubs share a consistent record system, but each answer carries the relevant controls, fault boundaries, consequences and official support entry point for that platform.

See the publication gate