← Watch feed

Informational 13 Bitcoin Committed Aug 26, 2025 · 17:33 UTC

fix(core): fix battery model (remove characteristics affetcted by temperature transition).

Trezor/Trezor firmware

2d4e292f View source ↗

Public commit record

What the developer wrote

Authored by kopecdav

62/100 · Adequate

fix(core): fix battery model (remove characteristics affetcted by temperature transition).

[no changelog]

✓ Specific, descriptive subject✓ Names a concrete action or component✓ Uses a recognizable type or scope! No meaningful explanatory body

The short version

What changed, and why it matters

This commit updates the battery fuel gauge calibration table for a specific Trezor battery model. It tweaks temperature points and the mathematical curves used to estimate charge level. There is no direct evidence in the commit that this fixes a security vulnerability; it appears to be a hardware calibration/modeling correction. The title says it removes characteristics affected by temperature transition, suggesting an accuracy improvement rather than a security fix.

Recommended action

Treat as a routine hardware-model calibration update. No immediate security action is required. If this battery model is used in a shipping Trezor device, verify through normal QA that battery percentage reporting remains accurate across temperatures. No patch urgency from a security standpoint.

Security signals we found

No security-relevant keywords in commit title or message

No changelog entry (suggests minor/internal fix)

Changes limited to static battery calibration constants

No modification of input validation, memory handling, or cryptographic code

No vendor security advisory or CVE referenced in commit

Technical analysis

Evidence from the diff

The patch modifies core/embed/sys/power_manager/fuel_gauge/battery_data_jyhpfl333838.h, which contains battery model parameters for the JYHPFL333838 cell. It adjusts BATTERY_TEMP_POINTS_DISCHG/CHG values and the rational-function coefficients for OCV (open-circuit voltage) discharge/charge curves at several temperature keys, plus capacity values. The changes are numerical recalibrations of the fuel-gauge model. No code logic, bounds checking, parsing, or cryptographic code is touched. The commit message frames this as removing characteristics affected by temperature transition, i.e., improving model stability/accuracy across temperature changes.

Changed components

core/embed/sys/power_manager/fuel_gauge/battery_data_jyhpfl333838.h

Inspect captured patch +50 / −50

diff --git a/core/embed/sys/power_manager/fuel_gauge/battery_data_jyhpfl333838.h b/core/embed/sys/power_manager/fuel_gauge/battery_data_jyhpfl333838.h
index d93fd55f9..303c61945 100644
--- a/core/embed/sys/power_manager/fuel_gauge/battery_data_jyhpfl333838.h
+++ b/core/embed/sys/power_manager/fuel_gauge/battery_data_jyhpfl333838.h
@@ -44,12 +44,12 @@
 // Discharge temperatures
 static const float BATTERY_TEMP_POINTS_DISCHG[BATTERY_NUM_TEMP_POINTS] = {
     0.80f,  5.78f,  10.64f, 15.55f, 20.65f,
-    25.42f, 31.41f, 35.41f, 40.39f, 45.29f};
+    25.43f, 31.41f, 35.41f, 40.38f, 45.28f};
 
 // Charge temperatures
 static const float BATTERY_TEMP_POINTS_CHG[BATTERY_NUM_TEMP_POINTS] = {
     2.32f,  7.28f,  12.60f, 17.51f, 22.50f,
-    27.46f, 32.31f, 37.36f, 42.34f, 47.35f};
+    27.38f, 32.31f, 37.36f, 42.34f, 47.37f};
 
 // Internal resistance curve parameters (rational function parameters
 // a+b*t)/(c+d*t)
@@ -62,10 +62,10 @@ static const float BATTERY_OCV_DISCHARGE_PARAMS[BATTERY_NUM_TEMP_POINTS][10] = {
     // Temperature: 0.80°C (key: 0)
     {
         0.126550f, 3.211777f,  // m, b (linear segment)
-        16.395191f, 128.363626f, 5.345433f,
-        38.414635f,  // a1, b1, c1, d1 (first rational segment)
-        1257.147271f, -1252.056059f, 379.613560f,
-        -378.115976f  // a3, b3, c3, d3 (third rational segment)
+        19.098931f, 149.532130f, 6.226951f,
+        44.749610f,  // a1, b1, c1, d1 (first rational segment)
+        1209.541847f, -1204.643391f, 365.238423f,
+        -363.797538f  // a3, b3, c3, d3 (third rational segment)
     },
     // Temperature: 5.78°C (key: 5)
     {
@@ -86,10 +86,10 @@ static const float BATTERY_OCV_DISCHARGE_PARAMS[BATTERY_NUM_TEMP_POINTS][10] = {
     // Temperature: 15.55°C (key: 15)
     {
         0.114185f, 3.232650f,  // m, b (linear segment)
-        53.301731f, 494.341291f, 17.390648f,
-        147.397127f,  // a1, b1, c1, d1 (first rational segment)
-        3148.601582f, -3139.694761f, 947.559853f,
-        -944.961920f  // a3, b3, c3, d3 (third rational segment)
+        60.048245f, 556.913282f, 19.591820f,
+        166.054156f,  // a1, b1, c1, d1 (first rational segment)
+        3200.736593f, -3191.682291f, 963.249686f,
+        -960.608735f  // a3, b3, c3, d3 (third rational segment)
     },
     // Temperature: 20.65°C (key: 20)
     {
@@ -99,13 +99,13 @@ static const float BATTERY_OCV_DISCHARGE_PARAMS[BATTERY_NUM_TEMP_POINTS][10] = {
         1180.804882f, -1178.074609f, 355.167808f,
         -354.373464f  // a3, b3, c3, d3 (third rational segment)
     },
-    // Temperature: 25.42°C (key: 25)
+    // Temperature: 25.43°C (key: 25)
     {
-        0.117951f, 3.235429f,  // m, b (linear segment)
-        89.871275f, 1253.014022f, 29.329382f,
-        376.569165f,  // a1, b1, c1, d1 (first rational segment)
-        1131.880318f, -1129.339379f, 340.039336f,
-        -339.304723f  // a3, b3, c3, d3 (third rational segment)
+        0.117543f, 3.236008f,  // m, b (linear segment)
+        78.102339f, 1077.942159f, 25.484299f,
+        323.846567f,  // a1, b1, c1, d1 (first rational segment)
+        1130.318095f, -1127.865886f, 339.544458f,
+        -338.836536f  // a3, b3, c3, d3 (third rational segment)
     },
     // Temperature: 31.41°C (key: 30)
     {
@@ -123,21 +123,21 @@ static const float BATTERY_OCV_DISCHARGE_PARAMS[BATTERY_NUM_TEMP_POINTS][10] = {
         4774.132278f, -4767.725320f, 1431.719239f,
         -1429.869351f  // a3, b3, c3, d3 (third rational segment)
     },
-    // Temperature: 40.39°C (key: 40)
+    // Temperature: 40.38°C (key: 40)
     {
-        0.123437f, 3.237152f,  // m, b (linear segment)
-        203.753833f, 3441.209337f, 66.623422f,
-        1035.896296f,  // a1, b1, c1, d1 (first rational segment)
-        1068.509706f, -1066.951782f, 320.376374f,
-        -319.926907f  // a3, b3, c3, d3 (third rational segment)
+        0.123696f, 3.237016f,  // m, b (linear segment)
+        221.044970f, 3715.383819f, 72.272903f,
+        1118.389323f,  // a1, b1, c1, d1 (first rational segment)
+        -4039.944265f, 4034.063152f, -1211.294227f,
+        1209.598810f  // a3, b3, c3, d3 (third rational segment)
     },
-    // Temperature: 45.29°C (key: 45)
+    // Temperature: 45.28°C (key: 45)
     {
-        0.124998f, 3.235772f,  // m, b (linear segment)
-        1819.150259f, 31026.915232f, 595.177551f,
-        9343.581417f,  // a1, b1, c1, d1 (first rational segment)
-        41239.010522f, -41183.173619f, 12365.128437f,
-        -12349.005616f  // a3, b3, c3, d3 (third rational segment)
+        0.125006f, 3.235912f,  // m, b (linear segment)
+        151.467401f, 2582.526900f, 49.550052f,
+        777.691108f,  // a1, b1, c1, d1 (first rational segment)
+        1112.445343f, -1110.999778f, 333.537185f,
+        -333.119361f  // a3, b3, c3, d3 (third rational segment)
     }};
 
 // Charge OCV curve parameters for each temperature
@@ -169,10 +169,10 @@ static const float BATTERY_OCV_CHARGE_PARAMS[BATTERY_NUM_TEMP_POINTS][10] = {
     // Temperature: 17.51°C (key: 15)
     {
         0.115653f, 3.274031f,  // m, b (linear segment)
-        64.044330f, 529.396718f, 20.054090f,
-        157.624172f,  // a1, b1, c1, d1 (first rational segment)
-        1058.938754f, -1022.297695f, 317.911706f,
-        -307.869074f  // a3, b3, c3, d3 (third rational segment)
+        237.696958f, 1964.826751f, 74.429637f,
+        585.013431f,  // a1, b1, c1, d1 (first rational segment)
+        968.862408f, -935.338129f, 290.869232f,
+        -281.680851f  // a3, b3, c3, d3 (third rational segment)
     },
     // Temperature: 22.50°C (key: 20)
     {
@@ -182,13 +182,13 @@ static const float BATTERY_OCV_CHARGE_PARAMS[BATTERY_NUM_TEMP_POINTS][10] = {
         983.725464f, -950.493228f, 295.209174f,
         -286.098635f  // a3, b3, c3, d3 (third rational segment)
     },
-    // Temperature: 27.46°C (key: 25)
+    // Temperature: 27.38°C (key: 25)
     {
-        0.108980f, 3.280729f,  // m, b (linear segment)
-        13.408572f, 195.788230f, 4.191912f,
-        58.632729f,  // a1, b1, c1, d1 (first rational segment)
-        1421.480447f, -1387.510482f, 425.138078f,
-        -415.819849f  // a3, b3, c3, d3 (third rational segment)
+        0.111950f, 3.273751f,  // m, b (linear segment)
+        -25.521502f, -274.597696f, -8.095046f,
+        -81.706277f,  // a1, b1, c1, d1 (first rational segment)
+        1073.930068f, -1053.131703f, 321.219989f,
+        -315.514254f  // a3, b3, c3, d3 (third rational segment)
     },
     // Temperature: 32.31°C (key: 30)
     {
@@ -214,13 +214,13 @@ static const float BATTERY_OCV_CHARGE_PARAMS[BATTERY_NUM_TEMP_POINTS][10] = {
         1018.218867f, -1006.960134f, 303.810937f,
         -300.720120f  // a3, b3, c3, d3 (third rational segment)
     },
-    // Temperature: 47.35°C (key: 45)
+    // Temperature: 47.37°C (key: 45)
     {
-        0.096072f, 3.287899f,  // m, b (linear segment)
-        19.109756f, 316.572653f, 6.001677f,
-        94.659222f,  // a1, b1, c1, d1 (first rational segment)
-        1023.376933f, -1010.269846f, 305.114363f,
-        -301.461068f  // a3, b3, c3, d3 (third rational segment)
+        0.102922f, 3.281457f,  // m, b (linear segment)
+        133.236246f, 1680.463569f, 42.563832f,
+        499.016826f,  // a1, b1, c1, d1 (first rational segment)
+        731.525161f, -722.630154f, 218.130924f,
+        -215.651760f  // a3, b3, c3, d3 (third rational segment)
     }};
 
 // Battery capacity data for each temperature
@@ -235,13 +235,13 @@ static const float BATTERY_CAPACITY[BATTERY_NUM_TEMP_POINTS][2] = {
     {355.86f, 378.79f},
     // Temperature: 20.65°C (key: 20)
     {362.69f, 394.38f},
-    // Temperature: 25.42°C (key: 25)
-    {358.49f, 352.85f},
+    // Temperature: 25.43°C (key: 25)
+    {357.80f, 383.75f},
     // Temperature: 31.41°C (key: 30)
     {361.17f, 379.75f},
     // Temperature: 35.41°C (key: 35)
     {357.76f, 366.75f},
-    // Temperature: 40.39°C (key: 40)
-    {358.06f, 383.63f},
-    // Temperature: 45.29°C (key: 45)
-    {354.19f, 350.75f}};
+    // Temperature: 40.38°C (key: 40)
+    {357.29f, 383.63f},
+    // Temperature: 45.28°C (key: 45)
+    {353.41f, 377.66f}};

Risk score

Why this scored 13/100

Our methodology →

Potential impact 2/30

Exploitability 1/25

Stealth signal 2/15

Affected reach 3/15

Confidence 3/10

Evidence quality 2/5

Human-validated context

Community notes

Notes can correct, qualify, or add evidence to the AI analysis. Every note shown here has been validated by a human moderator.

No validated notes yet.

The AI analysis stands alone for now. Submit a note if you can add evidence or important context.

What the developer wrote

What changed, and why it matters

Security signals we found

Evidence from the diff

Changed components

Why this scored 13/100

Community notes

Related watches

chore: remove libtropic's pin to develop branch

chore(core/embed): clear temporary buffer across Optiga/Tropic calls

test(core/ethereum): EIP-7702 tuple nonce must be non-zero