Hanafi
The sources give no view for it here.
الصلاة إلى مصحف في القبلة
هل تجوز الصلاة وفي جهة القبلة مصحف؟
Each school’s answer
In our wordsHanafi
Not stated in the sources
Maliki
Not stated in the sources
Shafi'i
Not stated in the sources
Hanbali
Not stated in the sources
The texts
٤٣٦ - مَسْأَلَةٌ: وَمَنْ صَلَّى وَفِي قِبْلَتِهِ مُصْحَفٌ فَذَلِكَ جَائِزٌ، مَا لَمْ يَتَعَمَّدْ عِبَادَةَ الْمُصْحَفِ؛ إذْ لَمْ يَأْتِ نَصٌّ، وَلَا إجْمَاعَ، بِالْمَنْعِ مِنْ ذَلِكَ. [مَسْأَلَةٌ صَلَّى وَفِي قِبْلَتِهِ نَارٌ أَوْ كَنِيسَةٌ أَوْ بِيعَةٌ أَوْ بَيْتُ نَارٍ]
From the schools’ own books
Maliki
The sources give no view for it here.
Shafi'i
The sources give no view for it here.
Hanbali
The sources give no view for it here.
What is «in our words» is our standard wording; the books’ texts stay as they are.